|
| year | consumption | change |
| 1980 | | NA |
| 1981 | | NA |
| 1982 | | NA |
| 1983 | | NA |
| 1984 | | NA |
| 1985 | | NA |
| 1986 | | NA |
| 1987 | | NA |
| 1988 | | NA |
| 1989 | | NA |
| 1990 | | NA |
| 1991 | | NA |
| 1992 | | NA |
| 1993 | .78 | NA |
| 1994 | .75 | -4.24 % |
| 1995 | .80 | 7.77 % |
| 1996 | .79 | -2.22 % |
| 1997 | .78 | -1.35 % |
| 1998 | .77 | -0.30 % |
| 1999 | .77 | -0.46 % |
| 2000 | .78 | 2.02 % |
| 2001 | .83 | 5.68 % |
| 2002 | .84 | 1.75 % |
| 2003 | .82 | -2.83 % |
| 2004 | .81 | -1.81 % |
| 2005 | .83 | 3.11 % |
| 2006 | .82 | -1.31 % |
| 2007 | .79 | -3.41 % |
| 2008 | .80 | 1.34 % |
| 2009 | .72 | -9.65 % |
| 2010 | .77 | 6.54 % |
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