at least in USA "According to some measures, such as the share of generics in the sales of molecules that have lost patent protection, this policy has been a great success (see Ellison et al. 1997, Berndt 2002, or Grabowski et al. 2014, who show that the market share of an originator drug typically drops below 20% after one year). Furthermore, the number of molecules facing generic competition has also soared since the early 2000s (Aitken et al. 2013).