|
| year | consumption | change |
| 1980 | .42 | NA |
| 1981 | .52 | 22.67 % |
| 1982 | .52 | -0.20 % |
| 1983 | .52 | 0.27 % |
| 1984 | .56 | 7.35 % |
| 1985 | .60 | 7.73 % |
| 1986 | .59 | -2.03 % |
| 1987 | .62 | 5.49 % |
| 1988 | .66 | 7.04 % |
| 1989 | .72 | 8.27 % |
| 1990 | .70 | -2.68 % |
| 1991 | .77 | 10.09 % |
| 1992 | .79 | 2.20 % |
| 1993 | .75 | -4.80 % |
| 1994 | .74 | -0.72 % |
| 1995 | .83 | 12.04 % |
| 1996 | .85 | 2.01 % |
| 1997 | .85 | 0.15 % |
| 1998 | .82 | -4.10 % |
| 1999 | .82 | 0.21 % |
| 2000 | .81 | -0.99 % |
| 2001 | .91 | 12.56 % |
| 2002 | .93 | 2.60 % |
| 2003 | .98 | 4.68 % |
| 2004 | .98 | 0.51 % |
| 2005 | 1.08 | 9.95 % |
| 2006 | 1.03 | -4.80 % |
| 2007 | .99 | -4.19 % |
| 2008 | 1.04 | 5.24 % |
| 2009 | .68 | -34.83 % |
| 2010 | .73 | 7.83 % |
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