The number of anti-Muslim hate crimes rose 91 percent in the first half of the year compared with the same period in 2016, a leading Muslim advocacy group said Monday.

The Council on American-Islamic Relations (CAIR) said the number of hate crimes spiked from the corresponding period of 2016, which was the worst year for anti-Muslim incidents since the civil rights organization began its current documenting system in 2013.

According to the report, the number of bias incidents in the first half of 2017 also rose by 24 percent on year.

“The presidential election campaign and the Trump administration have tapped into a seam of bigotry and hate that has resulted in the targeting of American Muslims and other minority groups,” said Zainab Arain, coordinator in CAIR’s Department to Monitor and Combat Islamophobia.

“If acts of bias impacting the American Muslim community continue as they have been, 2017 could be one of the worst years ever for such incidents.”

Read:Fighting the Wrong Enemy, why Americans Hate Muslims

The most frequent type of incidents documented by CAIR in the second quarter of 2017 involved harassment, defined as a non-violent or non-threatening incident. The second most common type of bias incidents were hate crimes and involved physical violence or property damage.

CAIR said the most prevalent trigger of anti-Muslim bias incidents in 2017 remains the victim’s ethnicity or national origin, accounting for 32 percent of the total.

“Twenty percent of incidents occurred because of an individual being perceived as Muslim. A Muslim woman’s headscarf was a trigger in 15 percent of incidents,” it added.

The report dataset is drawn primarily from the intakes CAIR conducts each year. With each case, civil rights and legal staff seek to ensure the highest possible level of accuracy.

According to CAIR’s 2016 report, anti-Muslim hate incidents rose over 40 percent compared to 2015, with a 44 percent increase in hate crimes targeting Muslims as well as a 57 percent increase in anti-Muslim bias incidents during that time.