If you read through the comments, you’ll see that an ER nurse (or doc) has already commented on the medical and forensic evidence issues. A simple Internet search will lead you to the same conclusions. If you have contradictory facts I’d like to see them. I’m always game for new information!
There are many studies - the 2% figure comes from compling cases where the false allegation was PROSECUTED. Very few of them are.
Several studies of cases of rape tend to conclude that about 20% of the cases are "no crime" -which means in the opinion of the investigator no crime occurred (which is different that believing a crime occurred, but lacking evidence to prosecute.)
Here's some info on it - I have a lot more if you'd like:
http://www.experts.com/Articles/False-Allegations-Criminal-Cases-Rape-Case-Example-By-Dan-Vogel