Transcription of interviews

Between September and November 2014, I will be conducting 6-10 interviews, each approximately 1 hour - 1.5 hours. I require someone to transcribe the interviews, word-for-word. This will entail high-level English language skills. Preferably, it would be wonderful to be able to have the interviews transcribed as we go along, rather than have them all done as a single batch. I am uncertain how many hours exactly it would take to transcribe, but I imagine that 5 hours per interview is a fair estimate (for a total of 30-50 hours work).