The chart to the right is the data I was referring to in my response to jbog when I wrote:
"You could also see the effect of the above in total TRx's. From 1999 to 2002, the percentage ot total scripts that were brand to generic were about 53% brand versus 47% generic. That started to change in 2003, and by mid 2006, only 37% of scripts were for branded drugs versus 63% for generic drugs. By the end of the decade, it will probably be a 25% brand / 75% generic split."