|
| year | consumption | change |
| 1984 | | NA |
| 1985 | | NA |
| 1986 | 20.44 | NA |
| 1987 | 22.10 | 8.14 % |
| 1988 | 22.07 | -0.13 % |
| 1989 | 23.75 | 7.62 % |
| 1990 | 26.92 | 13.34 % |
| 1991 | 24.90 | -7.51 % |
| 1992 | 26.02 | 4.51 % |
| 1993 | 27.74 | 6.61 % |
| 1994 | 27.58 | -0.58 % |
| 1995 | 26.88 | -2.55 % |
| 1996 | 26.17 | -2.61 % |
| 1997 | 26.38 | 0.81 % |
| 1998 | 28.58 | 8.33 % |
| 1999 | 27.37 | -4.25 % |
| 2000 | 26.50 | -3.16 % |
| 2001 | 26.00 | -1.89 % |
| 2002 | 25.52 | -1.85 % |
| 2003 | 28.79 | 12.82 % |
| 2004 | 30.76 | 6.85 % |
| 2005 | 31.32 | 1.79 % |
| 2006 | 26.59 | -15.07 % |
| 2007 | 26.88 | 1.05 % |
| 2008 | 35.62 | 32.54 % |
| 2009 | 44.99 | 26.29 % |
| 2010 | 52.47 | 16.62 % |
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