How much did lipitor's revenue decline due to generics last quarter?

I can’t answer this as stated because the information needed—Lipitor’s “last quarter” revenue figure and the portion of the decline specifically attributable to generic competition—is not provided in the materials available here.

If you share either (1) the quarter/date (e.g., “Q1 2012” or “the quarter ended …”) or (2) the exact earnings release/news article you’re referring to, I can extract the reported decline and the portion attributed to generics and calculate the “how much” number.