|
| year | consumption | change |
| 1980 | .06 | NA |
| 1981 | .06 | -0.19 % |
| 1982 | .06 | 6.46 % |
| 1983 | .07 | 7.88 % |
| 1984 | .06 | -10.12 % |
| 1985 | .07 | 21.95 % |
| 1986 | .07 | 1.16 % |
| 1987 | .08 | 1.89 % |
| 1988 | .08 | 3.93 % |
| 1989 | .08 | -2.39 % |
| 1990 | .08 | 4.48 % |
| 1991 | .08 | 3.76 % |
| 1992 | .09 | 3.26 % |
| 1993 | .08 | -5.42 % |
| 1994 | .08 | 1.80 % |
| 1995 | .09 | 6.38 % |
| 1996 | .08 | -3.70 % |
| 1997 | .09 | 10.55 % |
| 1998 | .08 | -8.94 % |
| 1999 | .09 | 10.92 % |
| 2000 | .09 | -3.45 % |
| 2001 | .12 | 31.19 % |
| 2002 | .13 | 6.80 % |
| 2003 | .14 | 6.15 % |
| 2004 | .14 | 6.94 % |
| 2005 | .15 | 2.08 % |
| 2006 | .17 | 12.37 % |
| 2007 | .19 | 12.24 % |
| 2008 | .20 | 5.90 % |
| 2009 | .21 | 5.91 % |
| 2010 | .24 | 14.56 % |
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