WASHINGTON (AFX) - The US economy expanded at a 1.7 pct annual rate in the fourth quarter, slightly stronger than the previous estimate of a 1.4 pct gain, the Commerce Department said. The final revision to Q4 GDP growth was stronger than expected by Wall Street economists. Their forecasts had projected that fourth quarter GDP growth would remain unchanged at 1.4 pct in the final estimate. The upward revision to Q4 GDP was primarily due to trade being less of a drag on economic growth than previously estimated. The report did not change the fundamental picture of the Sept-Dec quarter where the consumer and housing sectors were solid, but business investment remained weak and companies continued to shed inventories. Final sales -- GDP growth minus inventory behaviour -- rose at a revised 3.8 pct in the fourth quarter, up from the previous estimate of 3.6 pct rise. The GDP chain weighted price index fell 0.1 pct, compared with the previous estimate that the index fell 0.2 pct in the fourth quarter. This is the first decline in the GDP price index since Q1 1952. Excluding food and energy prices, the GDP chain-weighted index rose 0.4 pct, compared with the previous estimate of a 0.2 pct rise. The consumption price index rose 0.8 pct in the fourth quarter, compared with 0.7 pct in the prior estimate. Excluding food and energy prices, the PCE price index was up 2.7 pct, compared with the previous estimate of a 2.6 pct increase. This is the third and final revision to Q4 GDP. The first estimate of Q1 GDP will be released on Friday April 26. At the moment, for the first quarter, many economists forecast that GDP growth will reach between 4.0-5.0 pct, boosted by the end of a record period of inventory liquidation. Inventories subtracted slightly more from Q4 GDP growth than previously thought. Businesses subtracted 119.3 bln usd to inventories in the fourth quarter, down slightly from the previous estimate of 120.0 bln. The real change in business inventories subtracted 2.16 percentage points from Q4 GDP growth, slightly less than previous estimate that inventories subtracted 2.19 percentage points. Consumer spending in the fourth quarter was revised up marginally to a 6.1 pct gain from the previous estimate of a 6.0 pct gain. The trade sector subtracted less to Q4 GDP growth than previously thought. Trade subtracted 0.14 percentage points from Q4 GDP growth compared with the previous estimate of a 0.35 percentage point drop. Exports were revised to a fall of 10.9 pct, less than the previous estimate of a 12.2 pct fall. Imports were revised to a fall of 7.5 pct, deeper than previous estimate of a 6.9 pct fall. Business fixed investment fell 13.8 pct, slightly weaker than the previous estimate of a 13.1 pct fall. For the full year 2001 GDP rose 1.2 pct, down from 4.1 pct growth the previous year. This is the weakest performance for the US economy since 1991.