|
| year | consumption | change |
| 1980 | .01 | NA |
| 1981 | .01 | 42.86 % |
| 1982 | .01 | 26.24 % |
| 1983 | .01 | 5.02 % |
| 1984 | .01 | 10.75 % |
| 1985 | .01 | -9.58 % |
| 1986 | .01 | 2.76 % |
| 1987 | .02 | 13.72 % |
| 1988 | .02 | 9.25 % |
| 1989 | .02 | 11.92 % |
| 1990 | .02 | 7.67 % |
| 1991 | .02 | 4.70 % |
| 1992 | .02 | -7.18 % |
| 1993 | .02 | 6.83 % |
| 1994 | .02 | 11.95 % |
| 1995 | .02 | 2.59 % |
| 1996 | .02 | -0.98 % |
| 1997 | .02 | 1.85 % |
| 1998 | .02 | 0.20 % |
| 1999 | .02 | 0.00 % |
| 2000 | .03 | 5.87 % |
| 2001 | .03 | 1.79 % |
| 2002 | .03 | 2.02 % |
| 2003 | .03 | 7.24 % |
| 2004 | .03 | 1.84 % |
| 2005 | .03 | 4.72 % |
| 2006 | .03 | 4.77 % |
| 2007 | .04 | 10.87 % |
| 2008 | .04 | 2.09 % |
| 2009 | .03 | -14.00 % |
| 2010 | .03 | 0.00 % |
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