Historical Statistics of the United States Millennial Edition Online

		Ba4589	Ba4590	Ba4591
		Manufacturing	Class I steam railroads	Bituminous coal mining
Row	Year	Hours	Hours	Hours
1	1900	55.0	52.3	42.8
2	1901	54.3	52.0	41.0
3	1902	55.4	51.3	41.9
4	1903	54.3	52.3	40.8
5	1904	53.6	52.7	36.2

6	1905	54.5	50.6	38.0
7	1906	55.0	50.4	38.3
8	1907	54.3	53.7	42.0
9	1908	50.3	53.9	34.7
10	1909	53.1	51.5	37.5

11	1910	52.2	52.3	38.9
12	1911	51.7	53.1	37.8
13	1912	52.4	53.1	40.0
14	1913	50.9	54.8	41.6
15	1914	50.1	55.6	34.9

16	1915	50.4	55.1	36.9
17	1916	51.4	56.0	42.4
18	1917	51.0	55.2	43.9
19	1918	49.6	54.3	44.7
20	1919	46.1	46.8	35.2

21	1920	48.1	48.0	39.3
22	1921	45.3	43.8	26.3
23	1922	47.9	46.1	24.9
24	1923	48.9	46.2	31.1
25	1924	46.6	44.9	29.8

26	1925	47.9	45.0	33.9
27	1926	47.8	45.1	37.4
28	1927	47.4	44.7	33.3
29	1928	47.6	44.6	35.3
30	1929	48.0	44.8	38.1

31	1930	43.6	42.9	33.3
32	1931	40.2	40.7	28.1
33	1932	38.0	38.5	27.0
34	1933	37.6	38.4	29.3
35	1934	34.4	39.7	26.8

36	1935	36.4	40.2	26.2
37	1936	38.7	42.1	28.5
38	1937	37.9	42.1	27.7
39	1938	35.0	41.3	23.3
40	1939	37.3	42.1	26.8

41	1940	37.6	42.5	27.8
42	1941	40.0	44.0	30.7
43	1942	42.3	45.2	32.4
44	1943	44.1	47.2	35.8
45	1944	44.2	47.1	40.1

46	1945	42.4	46.4	38.4
47	1946	39.2	43.8	37.5
48	1947	39.2	43.8	35.7
49	1948	38.8	43.7	32.6
50	1949	38.0	41.0	27.9

51	1950	38.7	38.1	30.0
52	1951	38.9	37.9	30.2
53	1952	38.8	37.4	29.2
54	1953	38.6	37.1	29.5
55	1954	37.8	36.4	28.0

56	1955	38.5	37.1	32.4
57	1956	38.2	36.9	32.6
58	1957	37.8	36.5	31.5