|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | | 2.10 |
| 1987 | | 1.94 |
| 1988 | | 1.98 |
| 1989 | | 1.99 |
| 1990 | | 2.03 |
| 1991 | | 2.01 |
| 1992 | | 2.00 |
| 1993 | | 1.99 |
| 1994 | | 1.99 |
| 1995 | | 1.87 |
| 1996 | | 1.86 |
| 1997 | | 1.87 |
| 1998 | | 1.75 |
| 1999 | | 1.75 |
| 2000 | | 1.75 |
| 2001 | | 1.75 |
| 2002 | | 1.90 |
| 2003 | | 2.06 |
| 2004 | | 2.07 |
| 2005 | | 2.41 |
| 2006 | 1.85 | 3.31 |
| 2007 | 1.94 | 3.39 |
| 2008 | .93 | 1.64 |
| 2009 | .86 | 1.40 |
| 2010 | .86 | 1.33 |
|
|