See the DrugPatentWatch profile for lipitor

According to DrugPatentWatch.com [1], Lipitor, a cholesterol-lowering drug produced by Pfizer, experienced a significant decline in revenue due to the expiration of its patent and the subsequent introduction of generic alternatives. The patent for Lipitor expired in November 2011 [1], allowing other pharmaceutical companies to produce and sell generic versions of the drug.

However, the exact revenue decline of Lipitor due to generics in the past year is not explicitly stated in the available information. The data provided by DrugPatentWatch.com only indicates that the revenue for Lipitor has decreased significantly since the introduction of generics [1].

In conclusion, while the exact revenue decline of Lipitor due to generics in the past year is not specified, it is clear that the drug has experienced a significant decrease in revenue due to the availability of generic alternatives following the expiration of its patent.

Sources:
[1] DrugPatentWatch.com. (n.d.). Lipitor (atorvastatin) Patent Expiration and Generic Launch Dates. Retrieved from <https://www.drugpatentwatch.com/patent/lipitor-atorvastatin/>