Andrew Gelman had a link to my post about declining confidence in institutions, so I will give an update. First, since I was interested in trends, I just considered institutions for which there was twenty or more years of data. "Small business" narrowly missed, and does qualify this year, so here it is (along with the military and the police, which have similar levels of approval):
I think the 1994 figure is underestimated (or else everything else is overestimated), but even if you set them aside there seems to be an upward trend. Next, here is the change from 2016 to 2017:
Supreme Court +4
Criminal Justice +4
TV news +3
Big business +3
Small business -5
Eleven institutions improved, and only three declined. Differences of about 5 or more are statistically significant.
Finally, a possible explanation of confidence in the military is that it rises and falls depending on success or failure. That's probably a factor, but I don't think it's the whole story. In 1993, a couple of years after the success of the first Gulf War, 67% had a great deal or quite a bit of confidence in the military. In 2017, after long and inconclusive engagements in Iraq and Afghanistan, 75% did. I think that there has been a more general change, which Andrew Bacevich has talked about: the military doesn't ask much of the general public, and in return we don't ask questions.
[Additional data from the Roper Center for Public Opinion Research]