He really has no excuse for not knowing but being raised in this country how can he not know. Since he is over 50, I think it was brain freeze. That is not a desired presidential quality but I'll take that over the Muslim communist we have now.
Of course he knows it. He either simply misspoke, or was misheard, or translated the century/year thing backwards.
Note that the reporter wanted to make him sound really stupid, so it says “200 years” not “by 2”, which was the technical error.