https://blockchain.info/charts/n-transactions-excluding-chains-longer-than-10?timespan=all&daysAverageString=30

So about 120,000 "normal" transactions each day.

A 1 input -> 2 outputs is 226 bytes but sometimes we use 2 inputs for a "normal" transaction so let's take 300 bytes on average.

Then 120,000/(1,000,000/300x6x24) -> 25%