Gunshots fired into a mosque in Connecticut. Armed men protesting the “Islamization of America” outside Islamic centers in Texas. Death threats called in to mosques in Florida, Maryland and Virginia.

Anecdotal evidence suggests 2015, a year bookended by murderous attacks carried out in the name of Islam, has been one of the most intensely anti-Muslim periods in American history. A new study shared with CNN puts statistical heft behind that suspicion.

Through December 8, American mosques and Islamic centers have been the victims of vandalism, harassment and anti-Muslim bigotry at least 63 times this year, the Council on American-Islamic Relations says in the study. That’s the highest number since the Muslim civil rights group began keeping track in 2009 and a threefold increase over last year.

The previous high was 53 incidents in 2010, during the controversy over the “ground zero mosque” near the site of the 9/11 attack in New York. But many of those incidents concerned bias at zoning hearings for new mosques. This year’s hostilities have a sharper edge.

This November alone saw 17 anti-Muslim incidents at mosques, with the vehemence rising after terrorists aligned with the Islamic State killed 130 people in Paris. Death threats and vandalism appear to be spiking again since December 3, when a Muslim couple killed 14 people and injured 21 more in San Bernardino, California.

(There was little increase in incidents after one of the first prominent terrorists attacks of the year, against the magazine Charlie Hebdo in Paris on January 7.)

CAIR provided the data after CNN asked about the recent rise in reported anti-Muslim hate crimes. Neither the FBI nor CAIR have yet tallied the total number for 2015. But the data on mosques provides an early statistical look at how bad this year has been for American Muslims.

Typically, hate crimes against people — including Muslims — are twice as high as crimes against property, such as mosques, according to the FBI’s annual reports, leading many observers to predict that 2015 will witness the most anti-Muslim incidents since the terrorist attacks of 9/11.

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Corey Saylor, a CAIR spokesman, compiled the study based on media accounts and reports from the group’s regional chapters. He cautioned that the data is preliminary; the real number of incidents at mosques is likely higher. According to the Justice Department, hate crimes are often dramatically under-reported.

Still, CAIR’s study shows the depth of resentment against Muslims among some segments of the American population. The incidents occurred in nearly every region of the country, including the nation’s capital. (On Thursday, the Washington, D.C.-based CAIR itself was evacuated after it received hate mail containing a suspicious substance.)

“Daesh wants Americans to turn on each other, and with November seeing the highest number of mosque incidents since we started keeping data, it seems they are getting their wish,” said Saylor, using an alternative name for the Islamic State.

The incidents against mosques break down into four categories:

1. Damage, destruction or vandalism

2. Harassment, including the use of anti-Islamic slurs

3. Intimidation or threats

4. Clear bias during local zoning proceedings in which Muslims are seeking to build mosques

Since the Paris attacks, vandals have smashed mosque property and covered doorways with feces. Hackers replaced a Phoenix Islamic center’s homepage with a site that read “Vive le France.” A man in Falls Church, Virginia, left a fake explosive device at a mosque and battered its front gate.

The situation seems so dire that officials at the All Dulles Area Muslim Society in northern Virginia said the security firm they hired to protect the mosque quit this week. “They said, ‘We don’t know what’s going to happen, we can’t protect you,'” said Imam Mohamed Magid, the mosque’s leader. ADAMS has been vandalized twice in past years, according to members, but not recently.

Magid’s comments on Monday came minutes after Homeland Security Secretary Jeh Johnson, at a press conference at ADAMS, pleaded with Americans not to “throw a net of suspicion over Muslims.” Asked if Homeland Security will provide extra protection for mosques, a spokesman referred CNN to state and local law enforcement agencies.

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Since the San Bernardino, California, massacre, anti-Muslim incidents have reached well beyond mosques.

In recent weeks, Muslims have reported being attacked in parks while praying, bullied at school and spat on while driving. On Tuesday, a Muslim congressman, Rep. AndrĂ© Carson, D-Indiana, said he has received a death threat, which he attributed in part to politicians “who are fanning the flames of bigotry.”

Dalia Mogahed, director of research at the Institute of Social Policy and Understanding, said studies suggest that anti-Islamic sentiment seethes during presidential election years, when some politicians try to show their hawkish side by talking tough about Muslims.

During this election campaign, Donald Trump, the GOP front-runner, has proposed barring Muslim immigrants, surveillance of mosques and said he was open to the idea of creating a database of all Muslims living in the United States, ideas that struck some scholars as totalitarian and likely unconstitutional.

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According to CAIR, though, the anti-Islamic flames have been rising since August 2014, when ISIS released a video showing the beheading of two Americans. The horrific killings created an environment of “toxic hate,” the group said, in which some Americans lashed out against their Muslim neighbors.

Lori Peek, a sociologist at Colorado State University who has studied anti-Muslim backlash, says hate crimes are often more complex than they might seem. Some are carried out by drunk thrill-seekers with nothing better to do on a Saturday night. Others, which often occur after terrorist attacks, arise from a mistaken notion of “defending” the country from Muslim invaders.

In other words, one violent act, supposedly carried out in the name of Islam, is met by another violent act, supposedly carried out to combat Islam. Meanwhile, innocent American Muslims are caught in the middle. The effects of hate crimes can be long-lasting and psychologically devastating, according to studies, leading to depression, anxiety and other emotional trauma.

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As with the rise of ISIS in the last 18 months, the news keeps getting worse for American Muslims, Peek said, with every new attack like a drop of water falling into an overflowing sink. “Muslim Americans are feeling that they will never be able to say that this is in the past, that we will be accepted again into the fabric of America.”

Still, some American Muslims say they’ll keep trying, even if they are targeted.

Hours after the Paris attacks, a gunman fired five shots into Baitul Aman, a mosque that sits on a quiet stretch of Main Street in Meriden, Connecticut. Thankfully, no one was at the mosque at the time, said Mahmood Qureshi, president of the Ahamadiyya Muslim Community of Connecticut. Worshipers found the bullet holes the next day.

Initially, the congregation was rattled, but they decided to open their doors again. They invited the local community to an open house at the mosque the very next day.

“The person who fired at our mosque didn’t know us,” Qureshi said. “We have to do a better job of reaching out to people. But we are resilient.”

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