I would not waste money applying unless you have a really good shot at getting picked up. Not to stress anyone out, but this will be the most competitive year that STA-21 has seen thus far. Don't waste money on a bunch of colleges if you don't think you have a solid package.
I'm pretty sure we wouldnt be worried about applying to multiple schools if we weren't sure that our package is competitive. Theres no real way to know if this year is going to be more competitive or not. Yes, there has been a trend of the number of selectees going down but the number of applicants has gone down as well. Plus you have to take into account all the force retirements and retention borads that have all happened in the past year. So unless you are the Commander of Navy Manpower or some other type of flag officer that makes these decisions, theres really no way to tell.