|
| year | consumption | change |
| 1980 | .06 | NA |
| 1981 | .06 | -0.53 % |
| 1982 | .06 | 6.46 % |
| 1983 | .06 | 5.10 % |
| 1984 | .07 | 6.46 % |
| 1985 | .07 | -1.17 % |
| 1986 | .07 | 3.76 % |
| 1987 | .07 | 3.31 % |
| 1988 | .07 | 3.44 % |
| 1989 | .08 | 4.40 % |
| 1990 | .08 | 2.29 % |
| 1991 | .08 | -2.69 % |
| 1992 | .08 | 2.09 % |
| 1993 | .08 | 4.76 % |
| 1994 | .08 | 1.78 % |
| 1995 | .08 | 1.78 % |
| 1996 | .09 | 7.38 % |
| 1997 | .09 | 4.24 % |
| 1998 | .10 | 9.91 % |
| 1999 | .11 | 8.61 % |
| 2000 | .12 | 6.28 % |
| 2001 | .12 | 2.31 % |
| 2002 | .13 | 3.20 % |
| 2003 | .13 | 1.34 % |
| 2004 | .13 | 1.11 % |
| 2005 | .13 | 0.68 % |
| 2006 | .14 | 9.70 % |
| 2007 | .17 | 16.53 % |
| 2008 | .21 | 25.36 % |
| 2009 | .20 | -2.58 % |
| 2010 | .21 | 0.75 % |
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