|
| year | production | consumption |
| 1980 | | |
| 1981 | | 1.90 |
| 1982 | | 1.90 |
| 1983 | | 1.90 |
| 1984 | | .90 |
| 1985 | | 1.05 |
| 1986 | | 1.94 |
| 1987 | | 1.70 |
| 1988 | | 1.12 |
| 1989 | | 1.15 |
| 1990 | | 2.37 |
| 1991 | | 2.23 |
| 1992 | | 2.25 |
| 1993 | | 1.15 |
| 1994 | | 1.19 |
| 1995 | | 1.18 |
| 1996 | | 1.22 |
| 1997 | | 1.23 |
| 1998 | | 1.23 |
| 1999 | | 1.23 |
| 2000 | | 1.34 |
| 2001 | | 1.37 |
| 2002 | | 1.41 |
| 2003 | 36.07 | 1.41 |
| 2004 | 170.59 | 1.32 |
| 2005 | 176.66 | 1.45 |
| 2006 | 157.92 | 1.57 |
| 2007 | 144.20 | 1.84 |
| 2008 | 127.16 | 1.75 |
| 2009 | 119.47 | 1.75 |
| 2010 | 122.52 | 1.75 |
| 2011 | 114.96 | |
|
|