Year Number Of Units 1873 8690.00 1874 9419.00 1875 12494.0 1876 13654.0 1877 8488.00 1878 2381.00 1879 1285.00 1880 1431.00 1881 926.000 1882 1282.00 1883 995.000 1884 1347.00 1885 1673.00 1886 3082.00 1887 2413.00 1888 2534.00 1889 3476.00 1890 2545.00 1891 3553.00 1892 5203.00 1893 6460.00 1894 8921.00 1895 8436.00 1896 7945.00 1897 10797.0 1898 12924.0 1899 8501.00 1900 6149.00 1901 6295.00 1902 14051.0 1903 12313.0 1904 6981.00 1905 5312.00 1906 6514.00 1907 3717.00 1908 2610.00 1909 3429.00 1910 3524.00 1911 635.000 1912 499.000 1913 1579.00 1914 1287.00 1915 1326.00 1916 73.0000 1917 0.000000 1918 212.000 1919 744.000 1920 6809.00 1921 8856.00 1922 972.000 1923 3834.00 1924 10324.0 1925 4060.00 1926 16542.0 1927 18299.0 1928 23440.0 1929 11316.0 1930 14428.0 1931 14850.0 1932 16894.0 1933 20546.0 1934 10575.0 1935 10548.0 1936 11188.0