Year,Value,Contiguous U.S. (Lower 48),Precip,Apr-Jun,(in.)
1940,9.047
1941,9.498
1942,9.452
1943,8.842
1944,9.521
1945,10.196
1946,8.763
1947,10.845
1948,8.934
1949,8.922
1950,8.284
1951,8.768
1952,7.427
1953,9.117
1954,7.898
1955,8.293
1956,7.128
1957,11.607
1958,8.867
1959,8.252
1960,8.152
1961,8.328
1962,7.778
1963,7.767
1964,8.423
1965,8.364
1966,6.709
1967,9.172
1968,8.729
1969,8.338
1970,7.959
1971,6.994
1972,8.414
1973,9.7
1974,8.612
1975,9.232
1976,8.41
1977,7.809
1978,9.243
1979,9.294
1980,8.838
1981,9.819
1982,10.37
1983,10.75
1984,10.027
1985,7.879
1986,9.318
1987,8.121
1988,7.002
1989,9.681
1990,9.43
1991,10.504
1992,8.528
1993,10.447
1994,8.827
1995,10.975
1996,9.397
1997,10.097
1998,9.278
1999,9.593
2000,8.926
2001,8.281
2002,7.979
2003,9.756
2004,9.409
2005,8.737
2006,7.515
2007,8.139
2008,8.676
2009,9.469
2010,9.206
2011,9.721
2012,6.963
2013,9.529
2014,9.241
2015,10.264
2016,8.733
2017,10.304
2018,8.969
2019,11.628
2020,8.512
2021,8.566
2022,8.741
2023,8.182
2024,9.614
2025,10.11