|
| year | consumption | change |
| 1980 | .21 | NA |
| 1981 | .20 | -5.74 % |
| 1982 | .24 | 17.53 % |
| 1983 | .22 | -5.98 % |
| 1984 | .27 | 20.26 % |
| 1985 | .24 | -9.41 % |
| 1986 | .26 | 5.15 % |
| 1987 | .26 | 2.56 % |
| 1988 | .27 | 2.18 % |
| 1989 | .28 | 3.77 % |
| 1990 | .34 | 23.17 % |
| 1991 | .40 | 15.94 % |
| 1992 | .47 | 19.60 % |
| 1993 | .53 | 12.58 % |
| 1994 | .56 | 4.47 % |
| 1995 | .56 | 0.78 % |
| 1996 | .58 | 2.77 % |
| 1997 | .61 | 5.45 % |
| 1998 | .62 | 2.06 % |
| 1999 | .59 | -4.63 % |
| 2000 | .64 | 8.58 % |
| 2001 | .50 | -22.06 % |
| 2002 | .53 | 4.90 % |
| 2003 | .58 | 10.87 % |
| 2004 | .71 | 20.69 % |
| 2005 | .89 | 25.68 % |
| 2006 | .95 | 7.24 % |
| 2007 | .99 | 4.30 % |
| 2008 | 1.01 | 2.34 % |
| 2009 | 1.09 | 7.09 % |
| 2010 | 1.10 | 1.66 % |
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