|
| year | consumption | change |
| 1980 | 42.10 | NA |
| 1981 | 39.20 | -6.89 % |
| 1982 | 29.90 | -23.72 % |
| 1983 | 25.70 | -14.05 % |
| 1984 | 24.70 | -3.89 % |
| 1985 | 24.00 | -2.83 % |
| 1986 | 23.20 | -3.34 % |
| 1987 | 20.62 | -11.12 % |
| 1988 | 18.39 | -10.81 % |
| 1989 | 21.10 | 14.72 % |
| 1990 | 20.40 | -3.29 % |
| 1991 | 21.40 | 4.88 % |
| 1992 | 21.86 | 2.15 % |
| 1993 | 21.40 | -2.08 % |
| 1994 | 23.93 | 11.79 % |
| 1995 | 21.70 | -9.29 % |
| 1996 | 20.44 | -5.83 % |
| 1997 | 22.47 | 9.92 % |
| 1998 | 21.84 | -2.79 % |
| 1999 | 23.35 | 6.92 % |
| 2000 | 24.68 | 5.67 % |
| 2001 | 29.00 | 17.52 % |
| 2002 | 28.31 | -2.36 % |
| 2003 | 31.34 | 10.69 % |
| 2004 | 32.45 | 3.54 % |
| 2005 | 34.94 | 7.67 % |
| 2006 | 37.16 | 6.37 % |
| 2007 | 38.56 | 3.76 % |
| 2008 | 41.41 | 7.39 % |
| 2009 | 37.25 | -10.05 % |
| 2010 | 36.75 | -1.35 % |
| 2011 | 50.00 | 36.06 % |
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