|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 7.03 | 15.47 |
| 1987 | 5.52 | 15.74 |
| 1988 | 6.76 | 11.15 |
| 1989 | 7.01 | 11.13 |
| 1990 | 4.20 | 12.00 |
| 1991 | 2.17 | 16.59 |
| 1992 | 1.75 | 22.72 |
| 1993 | 1.64 | 24.63 |
| 1994 | | 26.17 |
| 1995 | | 29.89 |
| 1996 | | 27.64 |
| 1997 | | 30.61 |
| 1998 | | 32.99 |
| 1999 | | 31.41 |
| 2000 | | 32.00 |
| 2001 | | 27.55 |
| 2002 | | 27.58 |
| 2003 | | 29.45 |
| 2004 | | 29.44 |
| 2005 | | 29.75 |
| 2006 | | 26.81 |
| 2007 | | 22.36 |
| 2008 | | 32.74 |
| 2009 | | 37.81 |
| 2010 | | 37.27 |
|
|