Contiguous U.S. CEI (All Steps Combined) Summer (June-August) 1910-2018
Date Actual Percent
1910 21.32
1911 17.06
1912 24.62
1913 20.10
1914 19.88
1915 37.16
1916 17.96
1917 20.62
1918 15.86
1919 21.90
1920 18.28
1921 17.84
1922 11.96
1923 16.70
1924 23.70
1925 17.14
1926 11.48
1927 25.66
1928 19.44
1929 13.74
1930 19.96
1931 23.14
1932 10.10
1933 18.40
1934 33.46
1935 8.62
1936 36.26
1937 13.96
1938 9.14
1939 9.66
1940 16.86
1941 23.30
1942 11.60
1943 19.20
1944 18.24
1945 16.56
1946 11.76
1947 13.22
1948 11.02
1949 16.92
1950 25.36
1951 22.84
1952 17.28
1953 19.44
1954 27.50
1955 15.10
1956 15.34
1957 10.86
1958 18.78
1959 10.32
1960 9.12
1961 25.16
1962 9.24
1963 13.74
1964 12.86
1965 20.70
1966 12.26
1967 24.44
1968 11.16
1969 5.40
1970 10.22
1971 8.12
1972 14.66
1973 15.68
1974 13.92
1975 15.60
1976 24.32
1977 10.06
1978 10.66
1979 15.10
1980 24.94
1981 12.48
1982 12.76
1983 26.00
1984 15.32
1985 13.86
1986 10.62
1987 11.94
1988 26.94
1989 16.44
1990 9.88
1991 14.44
1992 34.94
1993 32.60
1994 18.80
1995 19.96
1996 15.22
1997 12.72
1998 20.76
1999 14.76
2000 16.88
2001 14.56
2002 24.66
2003 23.74
2004 25.50
2005 18.02
2006 24.60
2007 32.60
2008 13.56
2009 19.20
2010 26.24
2011 38.40
2012 31.32
2013 24.68
2014 17.78
2015 22.80
2016 26.58
2017 23.28
2018 31.06