Source: National Air Pollutant Emission Trends, 1900-1998 (EPA, March 2000)
thousands of short tons		millions of short tons
93616	1940	93.616
91657	1941	91.657
92449	1942	92.449
93241	1943	93.241
94033	1944	94.033
94825	1945	94.825
95617	1946	95.617
96409	1947	96.409
97202	1948	97.202
97993	1949	97.993
102609	1950	102.609
99285	1951	99.285
99784	1952	99.784
100283	1953	100.283
100782	1954	100.782
101281	1955	101.281
101780	1956	101.78
102279	1957	102.279
102778	1958	102.778
103278	1959	103.278
109745	1960	109.745
106207	1961	106.207
108637	1962	108.637
111067	1963	111.067
113498	1964	113.498
115928	1965	115.928
118358	1966	118.358
120788	1967	120.788
123219	1968	123.219
125649	1969	125.649
129444	1970	129.444
129491	1971	129.491
128779	1972	128.779
125935	1973	125.935
119978	1974	119.978
116757	1975	116.757
120963	1976	120.963
120868	1977	120.868
122150	1978	122.15
118475	1979	118.475
117434	1980	117.434
114396	1981	114.396
112260	1982	112.26
117675	1983	117.675
116533	1984	116.533
117013	1985	117.013
111688	1986	111.688
110798	1987	110.798
118729	1988	118.729
106439	1989	106.439
98523	1990	98.523
100872	1991	100.872
97630	1992	97.63
98160	1993	98.16
102643	1994	102.643
93353	1995	93.353
95479	1996	95.479
94410	1997	94.41
89454	1998	89.454