Here are the overall 2015 PISA scores (averaging the Science, Reading, and Math scores equally), with color coding to put the various American scores (red bars) in perspective.
Keep in mind that some countries didn’t do a good job of rounding up everybody who was supposed to take the test, which probably serves to boost their scores slightly.
American whites went up 1 point since 2012′s PISA, while American Asians were down 31 points (roughly 3 tenths of a standard deviation). I don’t know why. In general, East Asian countries were down a little from 2012.
There were a number of big changes in the PISA from 2012 to 2015. I think they switched from paper to computer and made some other changes as well. So it’s probably best not to worry too much about score changes from 2012 to 2015.