|
| year | consumption | change |
| 1980 | .07 | NA |
| 1981 | .07 | 3.09 % |
| 1982 | .08 | 10.77 % |
| 1983 | .09 | 14.63 % |
| 1984 | .10 | 8.72 % |
| 1985 | .10 | 4.79 % |
| 1986 | .09 | -14.22 % |
| 1987 | .09 | -0.63 % |
| 1988 | .08 | -4.75 % |
| 1989 | .09 | 5.26 % |
| 1990 | .09 | -3.31 % |
| 1991 | .08 | -1.44 % |
| 1992 | .09 | 4.43 % |
| 1993 | .09 | 2.30 % |
| 1994 | .11 | 22.74 % |
| 1995 | .12 | 6.17 % |
| 1996 | .12 | 1.29 % |
| 1997 | .13 | 6.91 % |
| 1998 | .14 | 8.96 % |
| 1999 | .14 | 2.33 % |
| 2000 | .17 | 18.03 % |
| 2001 | .17 | -1.04 % |
| 2002 | .19 | 13.69 % |
| 2003 | .21 | 12.55 % |
| 2004 | .22 | 2.66 % |
| 2005 | .29 | 31.68 % |
| 2006 | .27 | -6.76 % |
| 2007 | .29 | 8.39 % |
| 2008 | .29 | -1.26 % |
| 2009 | .24 | -15.80 % |
| 2010 | .24 | -0.08 % |
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