|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.34 | 1.75 |
| 1987 | 2.45 | 1.75 |
| 1988 | 2.33 | 1.63 |
| 1989 | 2.45 | 1.64 |
| 1990 | 2.52 | 1.66 |
| 1991 | 2.45 | 1.64 |
| 1992 | 2.56 | 1.75 |
| 1993 | 2.57 | 1.75 |
| 1994 | 2.45 | 1.64 |
| 1995 | 2.52 | 1.71 |
| 1996 | 2.56 | 1.75 |
| 1997 | 2.27 | 1.50 |
| 1998 | 2.38 | 2.45 |
| 1999 | 3.69 | 3.81 |
| 2000 | 3.10 | 3.20 |
| 2001 | 2.90 | 3.51 |
| 2002 | 2.45 | 4.23 |
| 2003 | 2.52 | 2.99 |
| 2004 | 2.24 | 6.99 |
| 2005 | 3.13 | 7.13 |
| 2006 | 2.29 | 10.52 |
| 2007 | 1.31 | 10.82 |
| 2008 | 1.59 | 14.37 |
| 2009 | .98 | 17.53 |
| 2010 | 1.52 | 23.95 |
|
|