Merit-based scholarships

What are my chances of getting a merit-based scholarship at the University of Southern California?

According to this NY Times article which provides data from the College Board data on colleges and universities that award aid based on academic promise approximately 1 in every 4 students receive merit-based aid.

In 2011-12, 24% of freshman attending USC were in receipt of merit aid. The average amount of aid was $18874. The most generous were colleges like Colby-Sawyer College and Cooper Union for the Advancement of Science and Art (NY) where 88% and 71% received merit aid.