|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | | 1.27 |
| 1987 | | 1.23 |
| 1988 | | 1.47 |
| 1989 | | 1.41 |
| 1990 | | 1.49 |
| 1991 | | 1.53 |
| 1992 | | 2.96 |
| 1993 | | 2.96 |
| 1994 | | 3.07 |
| 1995 | | 3.11 |
| 1996 | | 3.10 |
| 1997 | | 3.11 |
| 1998 | | 4.80 |
| 1999 | | 3.11 |
| 2000 | | 4.02 |
| 2001 | | 3.82 |
| 2002 | | 3.88 |
| 2003 | | 3.99 |
| 2004 | | 4.10 |
| 2005 | | 4.21 |
| 2006 | | 4.31 |
| 2007 | | 4.44 |
| 2008 | | 4.54 |
| 2009 | | 4.66 |
| 2010 | | 4.70 |
|
|