The GameStop float is currently at 66.90 million and retail investors have locked in 45% of it, using transfer agent Computershare. As per Morningstar, 14.51 million of $GME are short :
If 45% of the float is locked by retail investors, that means approximately 30 million shares are currently in Computershare and if you add the 14.5 million shares short, that would come up to 44.5 million. If you divide that number to the current float of 66.90 , that give you 66.51 %.