| Year | Data | Change | Unit |
|---|---|---|---|
| 1949 | 15033 | 0 | Btu per Kilowatthour |
| 1950 | 14030 | -1003 | Btu per Kilowatthour |
| 1951 | 13641 | -389 | Btu per Kilowatthour |
| 1952 | 13361 | -280 | Btu per Kilowatthour |
| 1953 | 12889 | -472 | Btu per Kilowatthour |
| 1954 | 12180 | -709 | Btu per Kilowatthour |
| 1955 | 11699 | -481 | Btu per Kilowatthour |
| 1956 | 11456 | -243 | Btu per Kilowatthour |
| 1957 | 11365 | -91 | Btu per Kilowatthour |
| 1958 | 11085 | -280 | Btu per Kilowatthour |
| 1959 | 10970 | -115 | Btu per Kilowatthour |
| 1960 | 10760 | -210 | Btu per Kilowatthour |
| 1961 | 10650 | -110 | Btu per Kilowatthour |
| 1962 | 10558 | -92 | Btu per Kilowatthour |
| 1963 | 10482 | -76 | Btu per Kilowatthour |
| 1964 | 10462 | -20 | Btu per Kilowatthour |
| 1965 | 10453 | -9 | Btu per Kilowatthour |
| 1966 | 10415 | -38 | Btu per Kilowatthour |
| 1967 | 10432 | + 17 | Btu per Kilowatthour |
| 1968 | 10398 | -34 | Btu per Kilowatthour |
| 1969 | 10447 | + 49 | Btu per Kilowatthour |
| 1970 | 10494 | + 47 | Btu per Kilowatthour |
| 1971 | 10478 | -16 | Btu per Kilowatthour |
| 1972 | 10379 | -99 | Btu per Kilowatthour |
| 1973 | 10389 | + 10 | Btu per Kilowatthour |
| 1974 | 10442 | + 53 | Btu per Kilowatthour |
| 1975 | 10406 | -36 | Btu per Kilowatthour |
| 1976 | 10373 | -33 | Btu per Kilowatthour |
| 1977 | 10435 | + 62 | Btu per Kilowatthour |
| 1978 | 10361 | -74 | Btu per Kilowatthour |
| 1979 | 10353 | -8 | Btu per Kilowatthour |
| 1980 | 10388 | + 35 | Btu per Kilowatthour |
| 1981 | 10453 | + 65 | Btu per Kilowatthour |
| 1982 | 10454 | + 1 | Btu per Kilowatthour |
| 1983 | 10520 | + 66 | Btu per Kilowatthour |
| 1984 | 10440 | -80 | Btu per Kilowatthour |
| 1985 | 10447 | + 7 | Btu per Kilowatthour |
| 1986 | 10446 | -1 | Btu per Kilowatthour |
| 1987 | 10419 | -27 | Btu per Kilowatthour |
| 1988 | 10324 | -95 | Btu per Kilowatthour |
| 1989 | 10432 | + 108 | Btu per Kilowatthour |
| 1990 | 10402 | -30 | Btu per Kilowatthour |
| 1991 | 10436 | + 34 | Btu per Kilowatthour |
| 1992 | 10342 | -94 | Btu per Kilowatthour |
| 1993 | 10309 | -33 | Btu per Kilowatthour |
| 1994 | 10316 | + 7 | Btu per Kilowatthour |
| 1995 | 10312 | -4 | Btu per Kilowatthour |
| 1996 | 10340 | + 28 | Btu per Kilowatthour |
| 1997 | 10213 | -127 | Btu per Kilowatthour |
| 1998 | 10197 | -16 | Btu per Kilowatthour |
| 1999 | 10226 | + 29 | Btu per Kilowatthour |
| 2000 | 10201 | -25 | Btu per Kilowatthour |
| 2001 | 10333 | + 132 | Btu per Kilowatthour |
| 2002 | 10173 | -160 | Btu per Kilowatthour |
| 2003 | 10125 | -48 | Btu per Kilowatthour |
| 2004 | 10016 | -109 | Btu per Kilowatthour |
| 2005 | 9999 | -17 | Btu per Kilowatthour |
| 2006 | 9919 | -80 | Btu per Kilowatthour |
| 2007 | 9884 | -35 | Btu per Kilowatthour |
| 2008 | 9854 | -30 | Btu per Kilowatthour |
| 2009 | 9760 | -94 | Btu per Kilowatthour |
| 2010 | 9756 | -4 | Btu per Kilowatthour |
| 2011 | 9716 | -40 | Btu per Kilowatthour |
| 2012 | 9516 | -200 | Btu per Kilowatthour |
| 2013 | 9541 | + 25 | Btu per Kilowatthour |
| 2014 | 9510 | -31 | Btu per Kilowatthour |
| 2015 | 9319 | -191 | Btu per Kilowatthour |
| 2016 | 9232 | -87 | Btu per Kilowatthour |
| 2017 | 9213 | -19 | Btu per Kilowatthour |
| 2018 | 9104 | -109 | Btu per Kilowatthour |
| 2019 | 8905 | -199 | Btu per Kilowatthour |
| 2020 | 8905 | 0 | Btu per Kilowatthour |
| 2021 | 8905 | 0 | Btu per Kilowatthour |