In order to facilitate the settling of criminal justice debates, I thought I might link to a great source for answers: The Bureau of Justice Statistics. Here's a little snapshot of Felony Defendants in Large Urban Counties, from 2002.
As it turns out, An estimated 56,146 felony cases were filed in the State courts of the Nation's 75 largest counties during May 2002. About a fourth of defendants were charged with a violent offense. Two-thirds of defendants were charged with either a drug (36%) or property (30%) offense.
Thirty-eight percent of all defendants were detained until the court disposed of their case, including 6% who were denied bail. Murder defendants (92%) were the most likely to be detained. Nearly all (95%) convictions obtained during the 1-year study period were the result of a guilty plea. About 5 in 6 guilty pleas were to a felony. The mean prison sentence for violent felony convictions was about 10 years and the median was 5 years. For nonviolent felonies the mean was about 3 years and the median 2 years. Murder (40 years) and rape (10 years) convictions carried the longest median sentences.