Since the program started on June 28th, 31,743 unique individuals have used Biki, of which 43% have been "members" (most likely locals) and 57% have been "casual" users, most of which are likely tourists, but there's also some percentage of casual users who are locals just trying Biki out.  However, during the first four weeks of service, only 18% of users were "members", so the number of total local users in the current month is probably pretty close to half.