It's taken from Survey data. The size of respondents on the survey was enough to be used as a representative sample.
We examined the survey response in terms of battles played in a Submarine during 0.11.8.
The categories looked up were:
0 Battles in Submarines during 0.11.8
1-5 Battles in Submarines during 0.11.8
6-25 Battles in Submarines during 0.11.8
For those that fit into those categories, we provided the amounts there were against adding Submarines to the game. The group with the highest resistance to Submarines being added was the group that did not play them at all. As play went up, the resistance to Submarines being added reduced sharply. It could be assumed that someone playing a Submarine actively would want it to exist, but only 1-5 Battles is a small amount but still sees a very large difference in terms of negative sentiment.