Not off the top of my head. The bots shown in the chart above have a combined USD vote value of around $70k, so assuming their vote value is relatively constant day-to-day we could assume they're responsible for 7*70=$490k per week of votes. Steem.supply lists the USD value of the rewards fund as $2,900k which would make bots responsible for about 17% of all rewards dispersed on Steemit. Of course it's actually much more complex than that with reward shares and whale participation and a bunch of other things, but that seems like a reasonable ballpark figure.