Aggressive price hikes were a major trend in the MS market during 2007: price of Avonex increased 27%, whereas that of Copaxone and Rebif increased 18%, and Betaseron increased 16% (excluding a 13% increase in January 2008). Tysabri's price/patient/year is x2 higher so I suppose that's a good explanation for the modest annual 3% price increase. However, you are correct that only about one-third of Copaxone growth was driven by volume increases, price increase did the most.