|
| year | consumption | change |
| 1980 | 3.74 | NA |
| 1981 | 3.51 | -6.19 % |
| 1982 | 3.44 | -2.04 % |
| 1983 | 2.42 | -29.57 % |
| 1984 | 3.80 | 56.90 % |
| 1985 | 3.41 | -10.26 % |
| 1986 | 2.19 | -35.93 % |
| 1987 | 1.59 | -27.25 % |
| 1988 | 3.67 | 130.70 % |
| 1989 | 3.17 | -13.46 % |
| 1990 | 3.72 | 17.04 % |
| 1991 | 3.68 | -0.92 % |
| 1992 | 3.25 | -11.71 % |
| 1993 | 3.36 | 3.32 % |
| 1994 | 3.40 | 1.22 % |
| 1995 | 3.40 | 0.00 % |
| 1996 | 3.44 | 1.32 % |
| 1997 | 3.53 | 2.45 % |
| 1998 | 3.58 | 1.43 % |
| 1999 | 3.58 | 0.00 % |
| 2000 | 3.65 | 2.12 % |
| 2001 | 3.77 | 3.23 % |
| 2002 | 3.81 | 1.08 % |
| 2003 | 3.83 | 0.54 % |
| 2004 | 3.86 | 0.79 % |
| 2005 | 3.94 | 1.94 % |
| 2006 | 4.02 | 2.11 % |
| 2007 | 3.93 | -2.40 % |
| 2008 | 4.34 | 10.58 % |
| 2009 | 4.24 | -2.28 % |
| 2010 | 4.24 | 0.05 % |
| 2011 | | NA |
|
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