Florida’s state-run insurer is warning of 10 percent annual rate increases for years to come in Palm Beach and other South Florida counties because of what its CEO calls a “true crisis” in water-damage claims. But such losses actually decreased 20 percent since 2013, records requested by The Palm Beach Post show. Citizens Property Insurance Corp. officials say yes, but its number of customers is declining even more rapidly so the costs — down to $299 million in 2015 from $378 million in 2013 — have a much bigger proportional impact on rates.