The attack in San Bernardino, Calif. earlier this month is now the 75th Islamist-inspired terrorist attack or plot in the U.S., according to The Heritage Foundation’s timeline of Islamists plots. The timeline highlights the continued domestic and international threat Islamists have on our national security.

U.S. citizen Syed Rizwan Farook and his wife Tashfeen Malik, who was originally from Pakistan, attacked the Inland Regional Center for disabilities development – killing 14 of Farook’s coworkers. The two were later killed by law enforcement following a road-side shootout.

Found in possession of the couple: tactical gear, .233-caliber rifles, handguns, and 1,600 rounds of ammo at their time of capture; as well as an additional 3,000 rounds of ammo and 19 pipe bombs at their place of residence.

While the investigation is still on-going, reports have surfaced connecting Malik and Farook with the Islamic State, also known as ISIS.

There has been no confirmation the attack was ordered by ISIS or simply sparked by a mixture of radicalization and an office argument; reports show Malik had devoted allegiance to the ISIS. FBI has since noted the couple had been radicalized for “quite some time.”

In his address from the Oval Office the Sunday following the San Bernadino attack, President Barack Obama noted, “it is clear that the two of them had gone down the dark path of radicalization, embracing a perverted interpretation of Islam that calls for war against America and the West.”

According to the Interactive Timeline of Islamist Terror Plots Since 9/11, this will be the 64th executed by a U.S. national who had been radicalized. It also marks the 12th attack or plot within 2015 – making 2015 the most for attacks or plots within a single year since 2001. Past attacks and plots this year include a plot on a beach in the Florida Keys, a plot to attack a college campus, and an attack on a Muhammad art drawing contest in Texas.

The majority of attacks and plots by Islamist inspired terrorists in the past continue to be targeted towards military, police, and major cities like New York and Washington, D.C.

Thanks to law enforcement and the intelligence community most of the plots on the timeline have been stopped from becoming successful attacks. It’s important the U.S. continues to give their support in building strong counterterrorism measures domestically, while at the same time taking a strong stance against international terrorism.