Year,Value,Contiguous U.S. (Lower 48),Precip,Sep,(in.)
1940,1.689
1941,2.638
1942,2.225
1943,1.621
1944,2.318
1945,3.274
1946,2.444
1947,2.064
1948,1.804
1949,2.061
1950,2.614
1951,2.519
1952,1.396
1953,1.399
1954,1.777
1955,2.02
1956,1.348
1957,2.932
1958,2.801
1959,2.906
1960,2.165
1961,2.886
1962,2.534
1963,2.235
1964,2.47
1965,3.339
1966,2.26
1967,2.374
1968,2.244
1969,2.085
1970,2.748
1971,2.626
1972,2.702
1973,3.404
1974,2.533
1975,2.456
1976,2.433
1977,3.306
1978,2.513
1979,2.333
1980,2.799
1981,2.229
1982,2.795
1983,2.429
1984,2.194
1985,3.339
1986,3.943
1987,2.4
1988,3.097
1989,2.871
1990,2.116
1991,2.59
1992,2.328
1993,2.682
1994,2.113
1995,2.353
1996,3.458
1997,2.551
1998,2.366
1999,2.432
2000,2.114
2001,2.328
2002,2.657
2003,2.711
2004,2.908
2005,1.755
2006,2.721
2007,2.052
2008,2.625
2009,2.553
2010,2.696
2011,2.398
2012,2.201
2013,2.81
2014,2.483
2015,2.041
2016,2.679
2017,2.413
2018,3.605
2019,2.452
2020,2.485
2021,2.425
2022,1.877
2023,2.104
2024,2.429
2025,1.889