|
| year | production | consumption |
| 1984 | | 6.77 |
| 1985 | | 7.01 |
| 1986 | | 7.13 |
| 1987 | | 7.57 |
| 1988 | | 7.57 |
| 1989 | | 8.73 |
| 1990 | | 9.54 |
| 1991 | | 11.18 |
| 1992 | | 12.07 |
| 1993 | | 12.18 |
| 1994 | | 12.61 |
| 1995 | | 11.95 |
| 1996 | | 12.03 |
| 1997 | | 12.53 |
| 1998 | | 12.62 |
| 1999 | | 13.04 |
| 2000 | | 13.43 |
| 2001 | | 13.21 |
| 2002 | | 12.89 |
| 2003 | | 13.13 |
| 2004 | | 12.23 |
| 2005 | | 11.25 |
| 2006 | | 10.42 |
| 2007 | | 10.02 |
| 2008 | | 9.48 |
| 2009 | | 8.73 |
| 2010 | | 8.17 |
|
|