|
| year | consumption | change |
| 1980 | 4.30 | NA |
| 1981 | 4.30 | 0.00 % |
| 1982 | 4.70 | 9.30 % |
| 1983 | 5.40 | 14.89 % |
| 1984 | | NA |
| 1985 | 5.91 | NA |
| 1986 | 5.83 | -1.34 % |
| 1987 | 6.39 | 9.76 % |
| 1988 | 7.51 | 17.38 % |
| 1989 | 7.96 | 6.07 % |
| 1990 | 8.63 | 8.38 % |
| 1991 | 9.91 | 14.86 % |
| 1992 | 10.38 | 4.76 % |
| 1993 | 13.14 | 26.50 % |
| 1994 | 13.37 | 1.81 % |
| 1995 | 13.26 | -0.84 % |
| 1996 | 13.27 | 0.03 % |
| 1997 | 13.37 | 0.77 % |
| 1998 | 17.01 | 27.25 % |
| 1999 | 17.01 | 0.00 % |
| 2000 | 17.72 | 4.20 % |
| 2001 | 18.53 | 4.57 % |
| 2002 | 18.49 | -0.23 % |
| 2003 | 18.50 | 0.04 % |
| 2004 | 18.82 | 1.72 % |
| 2005 | 19.20 | 2.05 % |
| 2006 | 19.44 | 1.21 % |
| 2007 | 19.74 | 1.56 % |
| 2008 | 19.90 | 0.81 % |
| 2009 | 20.51 | 3.08 % |
| 2010 | 20.51 | 0.00 % |
| 2011 | 21.00 | 2.38 % |
|
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