|
| year | consumption | change |
| 1980 | .01 | NA |
| 1981 | .01 | -11.71 % |
| 1982 | .01 | -0.50 % |
| 1983 | .01 | 7.25 % |
| 1984 | .01 | 4.27 % |
| 1985 | .01 | 7.60 % |
| 1986 | .02 | 21.47 % |
| 1987 | .02 | -11.63 % |
| 1988 | .02 | 36.77 % |
| 1989 | .03 | 18.40 % |
| 1990 | .03 | 10.52 % |
| 1991 | .03 | 0.00 % |
| 1992 | .03 | 18.46 % |
| 1993 | .03 | -6.09 % |
| 1994 | .03 | 5.28 % |
| 1995 | .04 | 9.39 % |
| 1996 | .04 | -0.45 % |
| 1997 | .04 | 1.22 % |
| 1998 | .04 | 3.07 % |
| 1999 | .04 | 10.21 % |
| 2000 | .05 | 31.12 % |
| 2001 | .06 | 9.69 % |
| 2002 | .05 | -7.14 % |
| 2003 | .06 | 4.36 % |
| 2004 | .06 | 1.71 % |
| 2005 | .06 | 4.68 % |
| 2006 | .06 | 5.48 % |
| 2007 | .07 | 6.53 % |
| 2008 | .07 | 2.95 % |
| 2009 | .06 | -8.59 % |
| 2010 | .07 | 4.64 % |
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