Year Number Of Units 1857 8113.00 1858 7203.00 1859 6290.00 1860 7685.00 1861 6338.00 1862 4958.00 1863 5388.00 1864 5168.00 1865 8685.00 1866 12259.0 1867 13419.0 1868 14230.0 1869 11360.0 1870 9939.00 1871 12601.0 1872 15172.0 1873 16993.0 1874 14975.0 1875 15377.0 1876 11148.0 1877 11005.0 1878 8408.00 1879 10747.0 1880 9825.00 1881 19415.0 1882 19354.0 1883 20735.0 1884 18567.0 1885 15996.0 1886 14949.0 1887 20765.0 1888 20759.0 1889 21025.0 1890 15927.0 1891 20897.0 1892 22254.0 1893 19587.0 1894 15668.0 1895 17771.0 1896 16067.0 1897 15551.0 1898 15237.0 1899 18237.0 1900 15967.0 1901 22796.0 1902 25804.0 1903 25701.0 1904 27417.0 1905 31003.0 1906 29345.0 1907 29042.0 1908 22797.0 1909 24248.0 1910 23659.0 1911 26209.0 1912 29299.0 1913 29690.0 1914 29690.0 1915 37827.0