Roughly 90 percent of the assessments made about President Trump over the past year on the evening news programs of ABC, NBC and CBS were negative, according to a partisan study released Tuesday.

The three networks devoted 100 hours of airtime, or 34 percent of all evening news, covering Trump from Jan. 20, 2017, through the end of December, the report from the conservative Media Research Center stated. On its website, MRC says its "sole mission is to expose and neutralize the propaganda arm of the Left: the national news media."

Per the study, the federal and congressional investigations into possible collusion between Trump associates and Russia made up more than 20 hours of evening news coverage on the president.

The trio of networks also spent about 100 minutes each covering nonpolicy issues, including Trump's response to the Charlottesville, Va., white nationalist protest and his claim former President Barack Obama wiretapped his campaign headquarters at Trump Tower in New York City during the election.

More than 43 percent of the evening news focused on Trump-related controversies while 46 percent focused on policy-related issues.

The effort to repeal and replace Obamacare, which occupied much of the first half of 2017, received 475 minutes or nearly eight hours of coverage.

In second place was the North Korea nuclear showdown with six hours of coverage. Illegal immigration, the temporary travel ban, and tax reform each received between three and five hours total coverage.