<P> Using panel data estimates of export and import equations for 17 countries, Jakob B. Madsen (2002) estimated the effects of increasing tariff and non-tariff trade barriers on worldwide trade during the period 1929--1932 . He concluded that real international trade contracted somewhere around 33% overall . His estimates of the impact of various factors included about 14% because of declining GNP in each country, 8% because of increases in tariff rates, 5% because of deflation - induced tariff increases, and 6% because of the imposition of non-tariff barriers . </P> <P> The new tariff imposed an effective tax rate of 60% on more than 3,200 products and materials imported into the United States, quadrupling previous tariff rates on individual items, but raising the average tariff rate to 19.2%, in line with average rates of that day . </P> <P> Unemployment was at 8% in 1930 when the Smoot--Hawley tariff was passed, but the new law failed to lower it . The rate jumped to 16% in 1931, and 25% in 1932--33 . There is some contention about whether this can necessarily be attributed to the tariff, however . It was not until World War II, during which "the American economy expanded at an unprecedented rate", that unemployment fell below 1930s levels . </P> <P> Imports during 1929 were only 4.2% of the United States' GNP and exports were only 5.0% . Monetarists, such as Milton Friedman, who emphasize the central role of the money supply in causing the depression, note that the Smoot--Hawley Act only had a contributory effect on the entire U.S. economy . </P>

During the 1920s what was the primary goal of a protective tariff