|
| year | consumption | change |
| 1980 | 15.60 | NA |
| 1981 | 14.20 | -8.97 % |
| 1982 | 13.80 | -2.82 % |
| 1983 | 13.80 | 0.00 % |
| 1984 | 12.70 | -7.97 % |
| 1985 | 11.90 | -6.30 % |
| 1986 | 11.89 | -0.11 % |
| 1987 | 12.60 | 6.02 % |
| 1988 | 13.67 | 8.51 % |
| 1989 | 13.38 | -2.18 % |
| 1990 | 13.45 | 0.52 % |
| 1991 | 11.43 | -15.01 % |
| 1992 | 13.00 | 13.80 % |
| 1993 | 10.85 | -16.57 % |
| 1994 | 10.71 | -1.28 % |
| 1995 | 10.91 | 1.83 % |
| 1996 | 11.09 | 1.71 % |
| 1997 | 11.17 | 0.66 % |
| 1998 | 11.75 | 5.23 % |
| 1999 | 11.16 | -5.00 % |
| 2000 | 10.74 | -3.79 % |
| 2001 | 11.76 | 9.50 % |
| 2002 | 12.19 | 3.64 % |
| 2003 | 12.74 | 4.50 % |
| 2004 | 13.27 | 4.21 % |
| 2005 | 14.07 | 6.03 % |
| 2006 | 14.54 | 3.33 % |
| 2007 | 14.80 | 1.78 % |
| 2008 | 11.86 | -19.86 % |
| 2009 | 12.96 | 9.31 % |
| 2010 | 14.43 | 11.33 % |
| 2011 | 19.00 | 31.64 % |
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