Only 26% of respondents in an August 13, 2017 survey conducted by the Annenberg Public Policy Center could correctly name all three branches of the federal government. And an additional 33% (the largest percentage of respondents to this particular survey question) couldn't name ANY branch at all. Those who could name at least one branch totaled 27% and two branches, another 13% (1% of respondents refused to answer the question).
The survey is littered with questions about government, our Constitution, the rights of U.S. citizens (and non-citizens) and so forth. "Ouch!" is all I have to say: