|
| year | consumption | change |
| 1980 | | NA |
| 1981 | | NA |
| 1982 | | NA |
| 1983 | | NA |
| 1984 | | NA |
| 1985 | 8.85 | NA |
| 1986 | 8.85 | 0.03 % |
| 1987 | 8.85 | 0.00 % |
| 1988 | 8.76 | -1.06 % |
| 1989 | 8.78 | 0.27 % |
| 1990 | 8.57 | -2.47 % |
| 1991 | 8.57 | 0.00 % |
| 1992 | 8.67 | 1.23 % |
| 1993 | 8.70 | 0.27 % |
| 1994 | 8.76 | 0.69 % |
| 1995 | 8.85 | 1.02 % |
| 1996 | 8.86 | 0.20 % |
| 1997 | 8.94 | 0.82 % |
| 1998 | 8.94 | 0.00 % |
| 1999 | 8.94 | 0.00 % |
| 2000 | 8.98 | 0.47 % |
| 2001 | 9.00 | 0.27 % |
| 2002 | 9.16 | 1.70 % |
| 2003 | 9.16 | 0.00 % |
| 2004 | 9.13 | -0.27 % |
| 2005 | 9.09 | -0.44 % |
| 2006 | 9.30 | 2.29 % |
| 2007 | 9.60 | 3.23 % |
| 2008 | 9.08 | -5.46 % |
| 2009 | 9.30 | 2.47 % |
| 2010 | 9.08 | -2.41 % |
| 2011 | | NA |
|
|