|
| year | production | consumption |
| 1984 | | 1.48 |
| 1985 | | 2.66 |
| 1986 | | 3.14 |
| 1987 | | 3.27 |
| 1988 | | 3.30 |
| 1989 | | 3.37 |
| 1990 | | 3.31 |
| 1991 | | 3.53 |
| 1992 | | 3.71 |
| 1993 | | 3.72 |
| 1994 | | 3.75 |
| 1995 | | 3.79 |
| 1996 | | 3.87 |
| 1997 | | 3.85 |
| 1998 | | 3.44 |
| 1999 | | 3.31 |
| 2000 | | 3.61 |
| 2001 | | 4.16 |
| 2002 | | 4.38 |
| 2003 | | 4.39 |
| 2004 | | 5.01 |
| 2005 | | 5.01 |
| 2006 | | 5.37 |
| 2007 | | 5.56 |
| 2008 | | 5.45 |
| 2009 | | 5.31 |
| 2010 | | 4.80 |
|
|
