Year,US_land_kmt,US_discd_kmt
1935,0.40,0.10
1936,0.40,0.10
1937,0.50,0.20
1938,0.50,0.20
1939,0.60,0.20
1940,0.90,0.30
1941,1.30,0.40
1942,1.51,0.50
1943,1.33,0.40
1944,1.53,0.50
1945,1.21,0.40
1946,1.21,0.40
1947,1.12,0.30
1948,0.71,0.20
1949,1.22,0.40
1950,1.39,0.40
1951,0.86,0.20
1952,0.84,0.20
1953,0.84,0.20
1954,1.11,0.30
1955,1.32,0.40
1956,1.43,0.40
1957,2.43,0.70
1958,1.64,0.50
1959,1.56,0.50
1960,1.54,0.50
1961,1.82,0.60
1962,1.90,0.60
1963,3.60,1.00
1964,1.86,0.60
1965,1.51,0.50
1966,1.83,0.30
1967,1.59,0.80
1968,1.58,0.60
1969,1.42,0.30
1970,1.31,0.40
1971,1.72,0.70
1972,1.52,0.30
1973,1.72,0.00
1974,2.16,0.20
1975,2.22,0.00
1976,3.84,0.10
1977,3.72,0.00
1978,4.07,0.40
1979,4.44,0.50
1980,5.57,0.60
1981,3.57,0.60
1982,3.64,0.40
1983,2.21,0.30
1984,1.36,0.02
1985,1.17,0.15
1986,1.20,0.37
1987,1.35,0.27
1988,1.28,0.35
1989,1.12,0.44
1990,3.22,1.24
1991,1.74,0.51
1992,1.03,0.71
1993,0.79,0.15
1994,1.30,0.28
1995,1.33,0.35
1996,1.17,0.24
1997,1.11,0.28
1998,1.24,0.30
1999,1.21,0.15
2000,2.41,0.20
2001,2.50,0.48
2002,2.02,0.10
2003,1.80,0.17
2004,0.83,0.13
2005,0.67,