Nothing is divided by 2. The number of shares traded is exactly the number reported. If I buy 100,000 shares and it is the only trade of the day is the number 50,000 or 100,000? According to your logic there is a buy and a sell so instead of dividing by 2 why not multiply it by 2 so the trades were actuallly 200,000 - the buy and the sell.

So where did all those past few months shares come from?