Americans might be down on Congress — which has a 20% approval rating — and on the government in general, but we're apparently feeling pretty good about our federal agencies, with the folks who deliver our mail being at the top of the list.

Almost three-quarters of Americans give the U.S. Postal Service (USPS) a thumbs up, according to Gallup. Seventy-four percent of respondents say the postal service is going a "good" or "excellent" job.

After the post office, the departments and agencies drawing the highest approval are the Secret Service, Centers for Disease Control (CDC), CIA, NASA, and the FBI.

But like many things in America today, how an American feels about a particular agency or department often comes down along party lines.

For example, Republicans are much more likely to be down on the FBI, which President Donald Trump has repeatedly lambasted, while Democrats are more supportive of the law enforcement agency. Gallup found that fewer than half of Republicans, 46%, gave the FBI a high grade, compared to 66% of Democrats.

In general, Democrats tend to view the key federal government agencies and departments more positively when a Democrat is in the Oval Office, while the same holds true for Republicans when a member of the GOP is commander in chief.

However, for now at least, the agencies that seem be immune from partisan bickering include NASA, the CIA, IRS, Federal Reserve Board, USPS and the Secret Service.

The three agencies that score poorly overall are the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA) and the Department of Veterans' Affairs. The three entities draw more fair/poor ratings than excellent/good ratings.