|
| year | consumption | change |
| 1980 | 27.60 | NA |
| 1981 | 29.10 | 5.43 % |
| 1982 | 24.90 | -14.43 % |
| 1983 | 18.50 | -25.70 % |
| 1984 | 16.80 | -9.19 % |
| 1985 | 15.30 | -8.93 % |
| 1986 | 15.19 | -0.73 % |
| 1987 | 16.76 | 10.32 % |
| 1988 | 15.95 | -4.83 % |
| 1989 | 18.10 | 13.47 % |
| 1990 | 19.14 | 5.79 % |
| 1991 | 17.17 | -10.33 % |
| 1992 | 14.63 | -14.80 % |
| 1993 | 15.54 | 6.27 % |
| 1994 | 16.94 | 9.01 % |
| 1995 | 19.61 | 15.73 % |
| 1996 | 22.05 | 12.48 % |
| 1997 | 21.99 | -0.27 % |
| 1998 | 24.56 | 11.67 % |
| 1999 | 22.29 | -9.25 % |
| 2000 | 22.22 | -0.30 % |
| 2001 | 21.84 | -1.72 % |
| 2002 | 22.26 | 1.91 % |
| 2003 | 26.60 | 19.50 % |
| 2004 | 26.96 | 1.35 % |
| 2005 | 30.73 | 14.02 % |
| 2006 | 30.86 | 0.40 % |
| 2007 | 29.38 | -4.78 % |
| 2008 | 20.26 | -31.03 % |
| 2009 | 22.83 | 12.68 % |
| 2010 | 22.83 | 0.00 % |
| 2011 | 41.00 | 79.56 % |
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