The US saw 674 anti-Semitic incidents in 2012, nearly two-thirds of all attacks against religious groups, according to hate crime statistics released by the FBI Monday.

Despite constituting 61 percent of all anti-religious incidents, the number was a 13% downturn from 2011 and continued a steady downward trend in recent years. However, at least one group said the numbers were inaccurate.

In 2011, there were 771 anti-Jewish attacks, which represented an almost identical percentage of total religion-based attacks. The previous year saw 887 anti-Jewish attacks. There were 931 such incidents in 2009.

The trend in the FBI statistics reflects a finding by the Anti-Defamation League, which found in a poll released in October that anti-Semitism had declined three percent over the past two years.

The group that suffered the second-most attacks were Muslim-Americans, with 130 incidents.

The ADL criticized the report as faulty, charging that the drop in incidents was due, at least in part, to the failure of many government bodies to properly report hate crimes.

“Due to a deeply disturbing trend of under-reporting and under-participation by law enforcement agencies, including more than a dozen of the largest agencies in the United States, the 2012 Hate Crime Statistics Act report is seriously flawed,” National Director Abraham Foxman said in a written statement.

Of 18,000 law enforcement agencies in the US, only 13,022 provided data to the FBI in 2012, according to the ADL. In 2011, almost 14,500 agencies reported.

Foxman said a number of jurisdiction which had reported in previous years did not in 2012, representing a “significant setback in the progress that has been made over the past decade.”

“The Justice Department and the FBI should use every resource at their disposal to push harder to obtain this missing data, urging those cities and states that still have not provided their 2012 hate crime data to do so as quickly as possible,” he said.

The figures were collected by the Hate Crime Statistics Program of the FBI’s Uniform Crime Reporting Program. According to the FBI’s website, the presence of a particular bias in not enough to include the incident in the report. Only when an offender’s actions were motivated by a particular bias did investigators report the incident as a hate crime.

The report included a variety of crimes, including murder, manslaughter, rape, assault, intimidation, theft, and vandalism.

Congress defines a hate crimes as a “criminal offense against a person or property motivated in whole or in part by an offender’s bias against a race, religion, disability, ethnic origin or sexual orientation.”