|
| year | consumption | change |
| 1980 | 3.80 | NA |
| 1981 | 3.30 | -13.16 % |
| 1982 | 3.50 | 6.06 % |
| 1983 | 3.70 | 5.71 % |
| 1984 | 3.60 | -2.70 % |
| 1985 | 3.52 | -2.12 % |
| 1986 | 3.33 | -5.62 % |
| 1987 | 4.69 | 41.06 % |
| 1988 | 5.13 | 9.26 % |
| 1989 | 6.24 | 21.79 % |
| 1990 | 4.43 | -28.95 % |
| 1991 | 3.93 | -11.43 % |
| 1992 | 3.19 | -18.68 % |
| 1993 | 3.63 | 13.68 % |
| 1994 | 3.62 | -0.31 % |
| 1995 | 3.61 | -0.37 % |
| 1996 | 3.66 | 1.42 % |
| 1997 | 3.67 | 0.27 % |
| 1998 | 3.67 | 0.00 % |
| 1999 | 3.67 | 0.00 % |
| 2000 | 3.66 | -0.27 % |
| 2001 | 3.63 | -0.70 % |
| 2002 | 3.67 | 0.99 % |
| 2003 | 3.98 | 8.58 % |
| 2004 | 4.25 | 6.73 % |
| 2005 | 4.50 | 5.99 % |
| 2006 | 4.50 | -0.12 % |
| 2007 | 4.80 | 6.77 % |
| 2008 | 4.02 | -16.33 % |
| 2009 | 4.58 | 13.90 % |
| 2010 | 4.50 | -1.68 % |
| 2011 | | NA |
|
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