Ryan's right in that BBM did start to increase the number of sets they did each year in the late 1990's but I think real explosion happened in the 2003-2004 time frame.
It's pretty wild to look at the numbers. BBM has done a total of 514 sets in 25 years (well, 24 plus four months so far this year). The total number of sets they did their first 10 years (1991 to 2000) was only 64. The total for their next 10 years (2001-2010) was 260. Their total for just the four plus years since 2011 is 190!
After I did the counts, I decided that I needed to sit down and (finally) generate the complete list of BBM sets based on what was listed in SCM #110. It took a couple weeks to do, but I've now added this list to the Set Index page.
The sets are listed in the same order that they appear in SCM - the odd change in how the sets are listed around 2012 is due to a change they made, not me. There are a number of sets that they list in a particular year even though the year shown on the front of the card is different - for example the "Memories Of Uniform" set has "2015" on the front (so I consider it a 2015 set) but SCM includes it in the list of 2014 sets. I've included Engel's set notations where ever possible - since he hasn't done a modern checklist since mid-2008, his number stop there. Engel actually lists a number of sets that SCM does not - I'll be adding them to the set index separately. As far as I could tell, there was only one pre-2008 set that SCM listed that Engel did not which is pretty damned impressive if you ask me.
I've included links for any sets that I've written about - I think I've actually written posts on about 30% of the sets.
What I'd like to do is further expand the set index by including similar lists for the Epoch and Front Runner sets. The Calbee sets are fairly self expanatory and any major earlier sets are already well covered by Engel.