User blog comment:Kitahara/Recording drum expedition success rates/@comment-25779449-20150512042107/@comment-25730832-20150518072448

Seems pretty close to what I had too.

As for me, I must confessed that I messed up the amount of drum halfway through the experiment (when I was switching ships in and out for support expedition) so half+ of my data became dung. I'm re-running it again but this time I'll do expedition 37 and 38 alongside it.