Pakistan Tehreek-e-Insaf (PTI) chairman Imran Khan on Saturday announced to launch a countrywide membership drive in two months time. Speaking to newsmen in Islamabad, Khan said PTI has set a target to make four million members in the drive , which would continue for 60 to 75 days. PTI chief said he does not believe in family politics so all office-bearers of PTI from 'bottom to top' would be elected by its members.