Those reports to congress are not really worth anything. They're written by people with access only to open info that anyone could read anyway. They regurgitate data from other similar reports, Jane's books and various news bits.
And their purpose is to "scare" the congress members into thinking US Navy is going to get overrun by some enemy, so the congressmen vote on various acts that'd give the US DoD/USN more money. I wouldn't be surprised if such reports are actually funded through some channel via either USN itself or via arms industry companies in US that have sizable interests in various US DoD procurement programs.