|
| year | consumption | change |
| 1980 | .01 | NA |
| 1981 | .01 | -13.88 % |
| 1982 | .01 | 2.66 % |
| 1983 | .01 | -6.99 % |
| 1984 | .01 | -10.48 % |
| 1985 | .01 | -2.69 % |
| 1986 | .01 | 3.19 % |
| 1987 | .01 | -20.54 % |
| 1988 | .01 | -5.97 % |
| 1989 | .01 | 25.41 % |
| 1990 | .01 | 12.00 % |
| 1991 | .01 | 5.11 % |
| 1992 | .01 | 1.68 % |
| 1993 | .01 | -7.18 % |
| 1994 | .01 | 9.71 % |
| 1995 | .01 | 23.76 % |
| 1996 | .02 | 17.37 % |
| 1997 | .02 | 7.09 % |
| 1998 | .02 | 33.39 % |
| 1999 | .03 | 22.81 % |
| 2000 | .03 | 22.23 % |
| 2001 | .03 | 0.61 % |
| 2002 | .04 | 3.49 % |
| 2003 | .03 | -6.24 % |
| 2004 | .04 | 9.36 % |
| 2005 | .04 | 4.54 % |
| 2006 | .04 | 4.08 % |
| 2007 | .04 | 7.49 % |
| 2008 | .05 | 8.73 % |
| 2009 | .05 | -0.96 % |
| 2010 | .05 | -2.42 % |
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