|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.55 | 2.42 |
| 1987 | 2.43 | 2.23 |
| 1988 | 2.22 | |
| 1989 | 2.22 | 2.07 |
| 1990 | 3.48 | 2.14 |
| 1991 | 1.80 | 1.94 |
| 1992 | 2.11 | 1.96 |
| 1993 | 2.14 | 1.85 |
| 1994 | | |
| 1995 | 2.06 | 1.75 |
| 1996 | 3.40 | 1.70 |
| 1997 | 2.08 | 1.48 |
| 1998 | 2.08 | .95 |
| 1999 | 5.97 | .89 |
| 2000 | 8.24 | .80 |
| 2001 | 9.83 | .95 |
| 2002 | 9.47 | 1.06 |
| 2003 | 12.13 | .62 |
| 2004 | 19.24 | .40 |
| 2005 | 24.65 | 33.72 |
| 2006 | 17.54 | 16.96 |
| 2007 | 19.25 | 20.52 |
| 2008 | 3.22 | .25 |
| 2009 | 1.77 | .31 |
| 2010 | 7.96 | .23 |
|
|