Well, not every state uses the NAPLEX (which would eliminate UCSF), and no school that I know of publishes their average score. It's hard enough just to get the percentage of graduates who PASSED on the first try. And the numbers will be close to 100% for all the top schools, anyway (judging by the fact that it was a huge scandal at UT the year that we didn't have 100% passing). Graduation rates are also usually near 100% for all of those schools, the only real attrition being from those students who decide pharmacy is not for them.
The problem with any rankings in pharmacy is that there simply is not an objective standard to use. So reputation is used instead, which is completely self-perpetuating, since a large number of the faculty at various schools are graduates of the top 5-10 on that list.