Members of Congress earn a base salary of $174,000 a year, and many critics and members of the public believe that's way too much when you consider the relatively small number of accomplishments they notch in an average session.

But here are three reasons your member of Congress is actually underpaid.

1. They Work More Than You Think

Yes, it's true that the House of Representatives has averaged 137 "legislative days" a year since 2001.

And yes, it's true that the number of voting days represents about one day of work every three days, or fewer than three days a week.

But standing on the House floor isn't the sole responsibility of Congress. They also deal with constituent complains and questions, and provide services to residents of the 435 House districts across the United States.

Consider this: Members of Congress report working about 70 hours a week, roughly twice the length of the average American work week. Leaders of the both the House and Senate certainly put in more time than that.

Congressional Management Foundation studies have found that members of Congress report working 83 percent to 85 percent of their waking hours. They spend only 15 percent to 17 percent of their time on their personal lives.

2. Lots of Responsibility

Members of Congress are making important decisions serious issues that touch the lives of most, if not every, American. It's a lot of stress, and they're on call to both their leadership and constituents essentially around the clock.

Members of Congress also agree to give up much of their privacy after being elected. Elected officials live in a fishbowl, with their actions transparent for most of the world to see, especially in an age where social media make every move instantly accessible across the globe in a matter of seconds.

House members must also face the voters every two years, and senators are up for re-election every six years. So even though the turnover rate is relatively low in Congress, lawmakers must constantly be running for re-election even if it's not an election year if they want to hold onto their jobs.

3. They Could Make More in the Private Sector

Most members of Congress graduated from college - in all, 93 percent of the House and 99 percent of the Senate hold bachelor's degrees - and by and large they worked in business and law before being elected. 

Lawyers make an average annual salary of about $131,000 across the United States, but many with specialized areas of practice earn far more than that. Members of Congress are considered didn't get elected by being slouches; they're considered to be among the best and brightest in their respective professions.

As The Washington Post's Timothy B. Lee has written:

"... Members of Congress are part of America's elite. Their peers are bankers, entertainers, corporate executives, doctors, and lawyers. The most successful people in all of these professions make a lot more than $172,000. They're living in nicer houses, sending their kids to better schools, and taking fancier vacations than members of Congress are."

So, the lawyers among Congress may very well have gotten a starting salary at a big, white-shoe firm right out of law school that rivals that of their congressional salary. Most of those firms have been offering starting salaries of at least $160,000.

While it's true the congressional base salary of $174,000 is more than three times the median household income in the United States, it is still far less than what lawmakers could earn as lobbyists, for example. Lobbyists earn at least two, three and four times what members of Congress earn.