The funny thing is, on the official StatShark Discord someone actually asked this question, because that person was wondering why Naval stats for March-April looks so poor, and one of the StatShark developers answered this:
These stats are updated during the first week of each month:
How often are Global Stats Updated?
Global stats are always updated in the first week of each month, the exact day varies from month to month.
This is how the updates works, again quote from one of the StatShark devs:
Basically, they named it “Feb-march”, because this data also includes a few days from March (and exclude a few days from February). But you can threat them as February stats.
The last update was on April 5 (March-April stats). Next week we should see April-May stats, these stats will be interesting.
According to StatShark, the number of games played on popular vessels dropped by 2-3 times. Yes, about 50-66% less battles on these vessels than in the previous month (with old Naval Arcade aiming system), that’s a huge difference. The question is whether the player base will decline even further in the coming months. I suspect we will have even less players playing Naval in April, but we will see very soon. Just wait for the April-May stats, which will be released in the first week of May.