What are the Real Numbers of Americans in Afghanistan?

As the State Depart­ment does its best to cov­er its fail­ures in evac­u­at­ing Amer­i­cans left in Afghanistan, what are the real num­bers that are wait­ing to get out? Are we receiv­ing the true num­bers? Is there risk of Amer­i­cans being left behind with a chance to recre­ate the Hostage Cri­sis in Iran from the Jim­my Carter Admin­is­tra­tion?