Tokyo stocks dropped more than One per cent in Monday morning trading amid growing concerns about the global economy following the US credit rating downgrade. The benchmark Nikkei 225 Stock Average lost 121.85 points, or 1.31 per cent, to trade at 9,178.03 at the end of morning trading at 11:00 am (0200 GMT). The broader-based Topix index was down 13.29 points, or 1.66 per cent, at 787.67, according to a report of the German Press Agency "DPA".