|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 1.25 | 1.54 |
| 1987 | 1.62 | 1.96 |
| 1988 | 1.66 | 1.66 |
| 1989 | 1.68 | 1.99 |
| 1990 | 1.68 | 2.03 |
| 1991 | 1.72 | 2.10 |
| 1992 | .98 | 1.36 |
| 1993 | 1.28 | 1.64 |
| 1994 | .55 | .96 |
| 1995 | 1.02 | 1.42 |
| 1996 | 1.02 | 1.42 |
| 1997 | 1.04 | 1.48 |
| 1998 | 1.04 | 1.48 |
| 1999 | 1.04 | 1.48 |
| 2000 | 1.06 | 1.52 |
| 2001 | | 1.55 |
| 2002 | 1.06 | 1.52 |
| 2003 | 1.07 | 1.54 |
| 2004 | 1.06 | 1.68 |
| 2005 | 1.32 | 1.85 |
| 2006 | .79 | 1.33 |
| 2007 | .73 | 1.37 |
| 2008 | .73 | 1.39 |
| 2009 | | .42 |
| 2010 | | .42 |
|
|
