Year,Value,Contiguous U.S. (Lower 48),Temp,May,(°F)
1940,59.192
1941,59.532
1942,57.264
1943,58.317
1944,60.652
1945,57.081
1946,57.71
1947,58.685
1948,60.361
1949,61.933
1950,59.5
1951,61.15
1952,61.005
1953,59.189
1954,58.885
1955,61.571
1956,61.897
1957,59.666
1958,63.078
1959,60.998
1960,59.845
1961,59.121
1962,62.624
1963,61.343
1964,61.814
1965,60.961
1966,60.653
1967,57.926
1968,58.587
1969,61.833
1970,61.453
1971,58.712
1972,61.005
1973,59.784
1974,60.87
1975,60.674
1976,59.501
1977,62.111
1978,60.183
1979,59.52
1980,60.871
1981,59.642
1982,61.345
1983,58.563
1984,60.797
1985,62.831
1986,61.665
1987,63.454
1988,62.129
1989,61.337
1990,59.636
1991,62.477
1992,61.829
1993,61.542
1994,61.617
1995,59.197
1996,61.511
1997,59.797
1998,62.829
1999,60.401
2000,63.647
2001,63.36
2002,59.876
2003,61.393
2004,62.664
2005,60.436
2006,63.286
2007,63.318
2008,60.417
2009,62.528
2010,60.743
2011,59.916
2012,64.646
2013,61.959
2014,62.123
2015,61.586
2016,61.369
2017,61.733
2018,66.523
2019,60.525
2020,62.149
2021,61.524
2022,63.156
2023,63.609
2024,63.035
2025,62.665