Two years is a long / short time.... a short / long time! (and 380 pages is a lot of work) Congratulations in either case!
Hopefully I can last at least that long myself, here's something I had whipped up for the 1st year of my comic:
I'd like to do several milestone images in time, but I think they'll be more spaced out as time goes by (year 1, year 10, page 100, page 1000, x-amount of subscribers, etc., etc.)