Congratulations!! And curse you for sniping me! This is the 400000th kancolle post! Here's to 500k!
Yup, KC is a pretty big when it comes to pic count on danbooru with (at the moment of writing) 8.3% of site's pictures apparently having it tagged. As far as I know the only IP related tags that have higher percentage than that are Touhou (14.3%) and Original (13.4%) with Fate (4.7%) being the 4th biggest.