context: Ashkelon was formally granted to Israel The average tariff rate on dutiable imports  increased from 40.1% in 1929 to 59.1% in 1932 (+19%). However, it was already consistently at high level between 1865 and 1913 (from 38% to 52%). Moreover, It had also risen sharply in 1861 (from 18.61% to 36.2%; +17.6), between 1863 and 1866 (from 32.62% to 48.33%; +15.7%), between 1920 and 1922 (from 16.4% to 38.1%; +21.7%), without producing global depressions.
question: In which year was the average tariff rate at its lowest?
answer: 1920