NYSE Daily Volume Statistics: Who Is Trading?

We always wanted to know, percentage-wise, who is trading - we knew that High frequency trading is a significant percentage and institutional investors as well - but here is the stat we spotted:

"Total daily volume in all stocks listed at the New York Stock Exchange went from about 2 billion shares a day five years ago, to an average of about 5 billion shares a day today. High-frequency trading now accounts for about 56 percent of trading volume, according to Tabb Group, but Tabb notes that this figure includes market makers. Five years ago, it was practically nothing.

Who's trading? Here's the latest breakdown of daily volume (source: Tabb Group):

High-Frequency Trading: 56 percent (includes proprietary trading shops, market makers, and high-frequency trading hedge funds)
Institutional: 17 percent (mutual funds, pensions, asset managers)
Hedge Funds: 15 percent
Retail: 11 percent
Other: 1 percent (non-proprietary banking)"

Statistics Source: Zero Hedge