|
| year | production | consumption |
| 1980 | | |
| 1981 | | |
| 1982 | | |
| 1983 | | |
| 1984 | | |
| 1985 | | |
| 1986 | | |
| 1987 | | |
| 1988 | | |
| 1989 | | |
| 1990 | | |
| 1991 | | |
| 1992 | .57 | 24.36 |
| 1993 | .71 | 30.02 |
| 1994 | .35 | 28.96 |
| 1995 | .35 | 34.61 |
| 1996 | .35 | 44.85 |
| 1997 | .46 | 31.71 |
| 1998 | .32 | 33.51 |
| 1999 | | 34.96 |
| 2000 | | 35.67 |
| 2001 | | 36.73 |
| 2002 | | 34.26 |
| 2003 | .18 | 35.81 |
| 2004 | .18 | 38.25 |
| 2005 | .18 | 39.69 |
| 2006 | .14 | 39.02 |
| 2007 | .11 | 39.66 |
| 2008 | .11 | 38.10 |
| 2009 | .11 | 36.09 |
| 2010 | .25 | 37.43 |
| 2011 | .07 | 32.00 |
|
|