I based my fleet size figures on the hull registration numbers seen on the sides of the Hyperion type vessels, which are our only indication of fleet sizes in the Babylon 5 universe. The EAS Hyperion seen in "A Voice in the Wilderness" had a hull registration number of "21,494 IAK." We don't know what the letters stand for, but the numbers speak for themselves. On the side of the Hyperion, the large number read 21, obviously to denote that the Hyperion was in the 21,000 line of capital ships made by the Earth Alliance