|
| year | consumption | change |
| 1980 | .01 | NA |
| 1981 | .01 | -2.39 % |
| 1982 | .01 | 1.22 % |
| 1983 | .01 | -0.55 % |
| 1984 | .01 | 45.58 % |
| 1985 | .01 | -1.14 % |
| 1986 | .01 | -43.04 % |
| 1987 | .01 | 37.92 % |
| 1988 | .01 | 28.28 % |
| 1989 | .02 | 16.25 % |
| 1990 | .01 | -11.02 % |
| 1991 | .01 | 5.46 % |
| 1992 | .05 | 221.82 % |
| 1993 | .04 | -14.52 % |
| 1994 | .05 | 20.16 % |
| 1995 | .05 | 1.38 % |
| 1996 | .05 | 0.52 % |
| 1997 | .05 | 0.81 % |
| 1998 | .05 | 0.37 % |
| 1999 | .05 | 0.00 % |
| 2000 | .05 | 2.09 % |
| 2001 | .05 | 0.00 % |
| 2002 | .05 | -4.58 % |
| 2003 | .05 | 2.76 % |
| 2004 | .04 | -14.92 % |
| 2005 | .05 | 18.24 % |
| 2006 | .04 | -14.30 % |
| 2007 | .04 | -7.80 % |
| 2008 | .04 | 12.94 % |
| 2009 | .03 | -36.44 % |
| 2010 | .03 | 0.22 % |
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