E-DRUG: Generic Dispensing Data

We are assembling information on pharmaceutical expenditures. One
     question is the share by volume and/or value of individual country
     markets covered by generic drugs. We have estimates for many
     developed countries, but are short on information for transitional and
     developing economies.
     
     Any suggestions on data or sources of data (if possible with
     definitions of what is meant by "generic drugs") would be appreciated.