|
| year | consumption | change |
| 1984 | | NA |
| 1985 | | NA |
| 1986 | 28.92 | NA |
| 1987 | 24.85 | -14.08 % |
| 1988 | 25.27 | 1.68 % |
| 1989 | 21.86 | -13.48 % |
| 1990 | 20.36 | -6.86 % |
| 1991 | 19.09 | -6.26 % |
| 1992 | 28.97 | 51.77 % |
| 1993 | 25.75 | -11.11 % |
| 1994 | 29.88 | 16.02 % |
| 1995 | 30.89 | 3.40 % |
| 1996 | 30.08 | -2.64 % |
| 1997 | 24.44 | -18.76 % |
| 1998 | 23.85 | -2.38 % |
| 1999 | 23.86 | 0.02 % |
| 2000 | 27.41 | 14.89 % |
| 2001 | 22.58 | -17.63 % |
| 2002 | 22.25 | -1.46 % |
| 2003 | 24.84 | 11.65 % |
| 2004 | 26.25 | 5.64 % |
| 2005 | 25.77 | -1.81 % |
| 2006 | 28.95 | 12.32 % |
| 2007 | 31.03 | 7.19 % |
| 2008 | 21.52 | -30.64 % |
| 2009 | 20.01 | -7.04 % |
| 2010 | 18.49 | -7.56 % |
|
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