|
| year | consumption | change |
| 1980 | .02 | NA |
| 1981 | .02 | 16.49 % |
| 1982 | .02 | -1.87 % |
| 1983 | .02 | -2.27 % |
| 1984 | .02 | 3.78 % |
| 1985 | .02 | -1.67 % |
| 1986 | .02 | 6.36 % |
| 1987 | .01 | -25.80 % |
| 1988 | .02 | 1.21 % |
| 1989 | .02 | 1.79 % |
| 1990 | .01 | -8.66 % |
| 1991 | .01 | -40.44 % |
| 1992 | .01 | -7.07 % |
| 1993 | .01 | -1.16 % |
| 1994 | .01 | 4.69 % |
| 1995 | .01 | 0.00 % |
| 1996 | .01 | 0.00 % |
| 1997 | .01 | 0.00 % |
| 1998 | .01 | 0.00 % |
| 1999 | .01 | 0.00 % |
| 2000 | .01 | 24.28 % |
| 2001 | .01 | 0.00 % |
| 2002 | .01 | 0.00 % |
| 2003 | .01 | 1.10 % |
| 2004 | .01 | -1.29 % |
| 2005 | .01 | 1.41 % |
| 2006 | .01 | 4.85 % |
| 2007 | .01 | 12.75 % |
| 2008 | .01 | -4.69 % |
| 2009 | .01 | -1.14 % |
| 2010 | .01 | 0.00 % |
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