Year	Thousand Units
1919	35.6000
1920	75.9000
1921	108.600
1922	124.300
1923	100.400
1924	94.8000
1925	164.400
1926	199.100
1927	284.400
1928	306.800
1929	315.700
1930	307.900
1931	231.300
1932	131.200
1933	132.900
1934	190.300
1935	213.200