In case you didn't know, today is Constitution Day, which we celebrate that document that has been America's law of the land since 1787, and over which we have fought, grappled, waged huge, expensive courtroom battles, interpreted, misinterpreted, and re-interpreted.

But the Montpelier Foundation, which upholds the legacy of James Madison, known historically as the "Father of the Constitution" and President No. 4, is interested in knowing how much We the People, the primary beneficiaries of the Constitution actually know about our governing laws. So through a survey, titled The State of the Constituiton: What Americans Know, they asked us. And to be honest, we didn't do too shabby.

In July, 988 people were surveyed on their knowledge of the U.S. Constitution. About 79% said they have "some" or "a lot" of knowledge about the document. But when broken down, it gets a little more complex.

Where an overall 31% said they knew a lot about the Constitution, only 16% of young people aged 18-24 said the same. About 28% percent of those surveyed said they'd read the entire treatise, and 67 percent said the last time they took a look at it was in high school or college. As for satisfaction, most people are happy with the Constitution as 88% say the document still works today.

As far as practical knowledge that's where Americans fall into a sketchy area. About 61% of participants thought the Consitution regulates interstate commerce; 89% guessed it's responsible for printing and regulating money; and 90% figured it's there for drawing up treaties, when actually all these things are done by the federal government.

Despite probably having skipped a few days of civics class in high school, Americans do feel, by 66%, that the Constitution does affect them on a day-to-day basis, 89% feel separation of church and state is important, and 92% feel the same way about rule of law.

You can test your knowledge of the U.S. Constitution here.