So at a pace of about 3,500 SBs for all of MLB, how unusual is this year in terms of history?

What you will be hearing a lot is comparison against recent history, because in the last 10 years have been down years in terms of SBs, averaging only 2,500 a year. So this year is BIG increase of about 40%

But in the previous 36 years (1974-2012), SBs averaged over 3,000 a year, and this includes the down years when everyone was waiting for home runs. 1987 is the previous high at close to 3,600.

In the 60 years ending 1973, the stolen base was a lost art, MLB only averaged 1,200 a year.

But, prior to 1915, over 3,000 SBs each year was the norm.

So for well over half of the last 136 years of MLB, over 3000 SBs has been the norm. From that perspective, this year is about 15% above average, not quite the major outlier it might seem.