|
| year | consumption | change |
| 1980 | .05 | NA |
| 1981 | .04 | -8.26 % |
| 1982 | .04 | 0.07 % |
| 1983 | .04 | 2.02 % |
| 1984 | .05 | 6.30 % |
| 1985 | .05 | 0.11 % |
| 1986 | .05 | 6.91 % |
| 1987 | .05 | -2.96 % |
| 1988 | .05 | 9.23 % |
| 1989 | .05 | 1.66 % |
| 1990 | .05 | 3.33 % |
| 1991 | .05 | -1.15 % |
| 1992 | .06 | 13.60 % |
| 1993 | .06 | -5.42 % |
| 1994 | .07 | 20.21 % |
| 1995 | .08 | 22.97 % |
| 1996 | .09 | 2.22 % |
| 1997 | .09 | 0.46 % |
| 1998 | .10 | 14.23 % |
| 1999 | .10 | 4.96 % |
| 2000 | .10 | -2.89 % |
| 2001 | .11 | 4.37 % |
| 2002 | .10 | -1.20 % |
| 2003 | .11 | 9.17 % |
| 2004 | .11 | -2.05 % |
| 2005 | .12 | 5.39 % |
| 2006 | .12 | 3.76 % |
| 2007 | .12 | 1.09 % |
| 2008 | .12 | -1.55 % |
| 2009 | .12 | -2.15 % |
| 2010 | .12 | 5.11 % |
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