The Senate Ethics Committee reviewed 93 instances of alleged wrongdoing in 2010 but ultimately dismissed all but four cases without any public action, according to an annual report released Monday.

According to its annual statistical report, the Ethics Committee received 84 complaints in 2010, including both public requests and reviews initiated within the panel, and carried over nine cases from 2009. At least four investigations remained open at the end of 2010, based on the statistics included in the committee’s report.

The committee dismissed 81 complaints outright. It ruled that it lacked jurisdiction in 56 instances, saying that “even if the allegations in the complaint are true, no violation of Senate rules would exist.” The other 25 cases were dropped because of lack of “any material violation … beyond mere allegation.”

The Ethics Committee’s staff conducted preliminary inquiries in the 12 complaints that weren’t dismissed outright. Half of those were first received by the panel in 2009, the report states.

The committee dismissed eight of those preliminary inquiries for “lack of substantial merit.” None of the preliminary investigations resulted in an adjudicatory review in 2010, nor did the committee dole out any private or public letters of admonition or otherwise punish any Members or aides last year.

One of the four inquiries that were still open by the end of 2010 is likely the panel’s investigation into Sen. John Ensign and allegations that the Nevada Republican tried to cover up an affair with the spouse of his former top aide. Ensign first acknowledged the affair with Cynthia Hampton, a campaign staff member married to administrative assistant Doug Hampton, in June 2009.

Both the Justice Department and the Federal Election Commission declined in late 2010 to pursue the allegation against Ensign.

The ethics panel is required to issue annual reports detailing its activities under the Honest Leadership and Open Government Act of 2007.

In addition to its investigations, the Ethics Committee is responsible for providing training to Senators and their offices, as well as issuing advice on how to comply with the chamber’s rules on issues including travel, gifts and conflicts of interest. The committee also reviews financial disclosures filed by Members and senior staff.