Some additional information about fights going to the ground to supplement what Cliff posted.
This article is in regards to an LAPD study. To quote the author, short conclusion here: "The LAPD study does not show that "90% of fights go to the ground." Instead, the LAPD study shows that 95% of altercations took on one of five familiar patterns (with which any street cop will be intimately familiar). It also shows that of that 95%, 62% ended up with both the officer and the suspect grappling on the ground."
I apologize for the thread drift, but thought this article was an interesting read for those engaged in this thread.