|
| year | consumption | change |
| 1980 | .02 | NA |
| 1981 | .02 | 13.63 % |
| 1982 | .02 | -19.64 % |
| 1983 | .02 | -11.76 % |
| 1984 | .02 | 14.31 % |
| 1985 | .02 | 1.62 % |
| 1986 | .02 | -3.59 % |
| 1987 | .01 | -23.95 % |
| 1988 | .01 | -0.61 % |
| 1989 | .01 | -33.13 % |
| 1990 | .01 | -3.58 % |
| 1991 | .01 | 15.18 % |
| 1992 | .01 | 14.19 % |
| 1993 | .02 | 22.92 % |
| 1994 | .02 | 2.17 % |
| 1995 | .01 | -14.52 % |
| 1996 | .01 | 6.84 % |
| 1997 | .02 | 9.57 % |
| 1998 | .02 | 26.53 % |
| 1999 | .02 | 6.40 % |
| 2000 | .02 | 9.26 % |
| 2001 | .02 | 2.79 % |
| 2002 | .02 | 1.66 % |
| 2003 | .02 | -2.17 % |
| 2004 | .02 | -10.25 % |
| 2005 | .02 | 10.09 % |
| 2006 | .02 | -4.89 % |
| 2007 | .02 | -0.64 % |
| 2008 | .02 | 2.24 % |
| 2009 | .02 | 0.94 % |
| 2010 | .02 | -0.53 % |
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