Roughly half the population approves of Trump(*).
(*) You can extend the vote results to cover the entire country because it's a large enough sample.
Ahem. The largest block of voters in the country is the one that did not give approval to either Trump or Clinton. They each received the explicit support of less than 30% of the eligible voters, rather than the nearly 50% which you imply.
Garbage about it being our "civic duty" to support one of the awful candidates offered to us, it should at least be acknowledged that the other 40+% of us exist, even if you approve of the republocrat/demopublican duopoly and don't think we deserve any actual political power.
Even among those who voted for Trump or Clinton, many (most? this election was worse than usual) were holding their noses while they did it, and hardly "approve" of either one. If you do a survey asking people whether they'd prefer to be hanged or drowned, you'll get an answer - that doesn't mean that people "approve" of the winner, though...