|
| year | consumption | change |
| 1980 | .10 | NA |
| 1981 | .10 | 1.76 % |
| 1982 | .11 | 17.16 % |
| 1983 | .10 | -9.10 % |
| 1984 | .13 | 26.87 % |
| 1985 | .15 | 11.04 % |
| 1986 | .14 | -3.78 % |
| 1987 | .14 | -0.66 % |
| 1988 | .14 | 2.60 % |
| 1989 | .15 | 7.31 % |
| 1990 | .16 | 3.80 % |
| 1991 | .17 | 3.58 % |
| 1992 | .17 | 4.01 % |
| 1993 | .13 | -25.45 % |
| 1994 | .14 | 6.98 % |
| 1995 | .15 | 8.85 % |
| 1996 | .15 | 1.80 % |
| 1997 | .16 | 3.97 % |
| 1998 | .17 | 7.61 % |
| 1999 | .18 | 4.78 % |
| 2000 | .19 | 8.27 % |
| 2001 | .21 | 6.23 % |
| 2002 | .23 | 9.79 % |
| 2003 | .24 | 8.22 % |
| 2004 | .25 | 0.76 % |
| 2005 | .26 | 4.26 % |
| 2006 | .28 | 9.22 % |
| 2007 | .26 | -8.92 % |
| 2008 | .32 | 25.26 % |
| 2009 | .29 | -9.59 % |
| 2010 | .30 | 4.34 % |
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