Washington, July 17 (BridgeNews) - After-tax profits at U.S. retailers fell to 2.0% of sales in the first quarter of 2001, from a revised 2.4% in the fourth quarter, the Commerce Department said Tuesday. * * * The first-quarter figure was up from a year earlier, when after-tax retail profits stood at 1.9% of sales. Retailers reported first quarter after-tax profits at $6.748 billion, down from a revised $9.128 billion in the fourth quarter. Retailer profits were up from $5.845 billion in the first quarter of 2000. Retailer sales totaled $338.561 billion in the first quarter, down from a revised $374.331 billion in the fourth quarter but up from $314.105 billion in the first quarter of 2000. The figures in this report are not seasonally adjusted and cover retailing firms with assets of $50 million or more.