|
| year | consumption | change |
| 1980 | 2.80 | NA |
| 1981 | 3.29 | 17.50 % |
| 1982 | 4.56 | 38.60 % |
| 1983 | 2.89 | -36.62 % |
| 1984 | 3.30 | 14.19 % |
| 1985 | 3.11 | -5.85 % |
| 1986 | 3.20 | 2.86 % |
| 1987 | 3.26 | 1.94 % |
| 1988 | 3.21 | -1.52 % |
| 1989 | 3.70 | 15.26 % |
| 1990 | 3.85 | 4.19 % |
| 1991 | 3.85 | 0.00 % |
| 1992 | 3.94 | 2.37 % |
| 1993 | 3.93 | -0.28 % |
| 1994 | 3.83 | -2.60 % |
| 1995 | 3.77 | -1.58 % |
| 1996 | 3.82 | 1.38 % |
| 1997 | 3.83 | 0.27 % |
| 1998 | 3.83 | 0.00 % |
| 1999 | 3.83 | 0.00 % |
| 2000 | 3.74 | -2.31 % |
| 2001 | 3.75 | 0.27 % |
| 2002 | 3.82 | 1.68 % |
| 2003 | 3.82 | 0.00 % |
| 2004 | 3.81 | -0.27 % |
| 2005 | 4.07 | 6.80 % |
| 2006 | 4.14 | 1.83 % |
| 2007 | 4.44 | 7.25 % |
| 2008 | 2.70 | -39.26 % |
| 2009 | 4.14 | 53.50 % |
| 2010 | 2.00 | -51.61 % |
| 2011 | | NA |
|
|