|
| 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 | .23 | NA |
| 1993 | .23 | 2.27 % |
| 1994 | .25 | 4.89 % |
| 1995 | .28 | 12.66 % |
| 1996 | .31 | 10.41 % |
| 1997 | .29 | -4.84 % |
| 1998 | .29 | -0.09 % |
| 1999 | .29 | 1.06 % |
| 2000 | .29 | -0.47 % |
| 2001 | .30 | 2.09 % |
| 2002 | .30 | 1.03 % |
| 2003 | .30 | -0.35 % |
| 2004 | .31 | 4.38 % |
| 2005 | .32 | 1.63 % |
| 2006 | .32 | -0.53 % |
| 2007 | .32 | 0.32 % |
| 2008 | .34 | 6.68 % |
| 2009 | .31 | -9.38 % |
| 2010 | .31 | 0.49 % |
|
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