|
| year | production | consumption |
| 1980 | | |
| 1981 | | |
| 1982 | | 7.80 |
| 1983 | | 10.60 |
| 1984 | | 10.70 |
| 1985 | | 12.90 |
| 1986 | | 13.60 |
| 1987 | | 13.95 |
| 1988 | | 13.19 |
| 1989 | | 13.43 |
| 1990 | | 13.71 |
| 1991 | | 12.77 |
| 1992 | | 7.21 |
| 1993 | | 6.97 |
| 1994 | | 6.67 |
| 1995 | | 6.36 |
| 1996 | | 6.00 |
| 1997 | | 5.62 |
| 1998 | | 5.33 |
| 1999 | | 5.33 |
| 2000 | | 4.72 |
| 2001 | | 4.69 |
| 2002 | | 4.79 |
| 2003 | | 3.81 |
| 2004 | | 4.12 |
| 2005 | | 4.44 |
| 2006 | | 4.40 |
| 2007 | | 4.51 |
| 2008 | | 4.98 |
| 2009 | | 36.25 |
| 2010 | | 36.25 |
| 2011 | | |
|
|