Originally Posted by notabook

Actually it's courtesy of wikipedia, which is courtesy of (at least partially) of the WHO.

Estimated per act risk for acquisition of HIV by exposure route
Blood Transfusion: 9,000
Childbirth: 2,500
Needle-sharing injection drug use: 67
receptive anal intercourse: 50
Percutaneous needle stick: 30
Receptive Penile-Vaginal Intercourse: 10
Insertive Anal Intercourse: 6.5
Insertive Penile-Vaginal Intercourse: 5
Receptive Fellatio: 1
Insertive Fellatio: 0.5

Anything else sweety? =)