Some economists argue that the Smoot-Hawley tariff act may have been a very bad idea but that it did not cause the Great Depression. They point out that exports only accounted for some seven percent of the U.S. gross national product in 1929 and the decline in U.S. exports in the ensuing years may have been caused by the depression itself and not solely by tariff retaliation. Some note that the U.S. had also enormously raised tariffs in 1922 and that this did not cause a depression.