Percentage of NYSE volume done on NYSE

What percentage of NYSE volume is done on the NYSE?

15 years ago I think the figure was around 90% but I am sure that figure has been slashed dramatically.

 

Not the complete data you want, but BATS.com shows the aggregate volume data.

 

http://markets.cboe.com/us/equities/market_share/

Set the Date as required.

Look under column Tape A - these are NYSE listed stocks.
Click on NYSE (P,N,A)

Take NYSE (N)
Compare with Total Consolidated volume for Tape A.
Now you have your percentage.

eg 2017-10-20, Tape A, NYSE (N) shows 900M, total consolidated volume is 3,394M, so about 26.5%