I went to the financial aid session at the admitted students day yesterday. The director spoke in detail about the 2nd year awards, and 70% of those students who apply usually get awards. It seems there are three types-- teaching assitantships, research/program assistants, and readers. TAs typically get 20k per semester, RA/PA positions get about 10.5k per semester, and I think readers get 6k per semester. The average award is 10.5k because there are many more RA positions available.
Hope this helps!