Show data table
| 1970 | 0.9716 Mt | 1989 | 0.8 Mt | 2008 | 0.5606 Mt |
| 1971 | 0.966 Mt | 1990 | 0.3752 Mt | 2009 | 0.5226 Mt |
| 1972 | 0.968 Mt | 1991 | 0.2582 Mt | 2010 | 0.7943 Mt |
| 1973 | 0.999 Mt | 1992 | 0.2315 Mt | 2011 | 0.8855 Mt |
| 1974 | 1.0734 Mt | 1993 | 0.2479 Mt | 2012 | 0.9771 Mt |
| 1975 | 1.1156 Mt | 1994 | 0.2473 Mt | 2013 | 0.9074 Mt |
| 1976 | 1.1616 Mt | 1995 | 0.2543 Mt | 2014 | 1.1822 Mt |
| 1977 | 1.2003 Mt | 1996 | 0.2759 Mt | 2015 | 1.233 Mt |
| 1978 | 1.2316 Mt | 1997 | 0.271 Mt | 2016 | 1.3852 Mt |
| 1979 | 1.4371 Mt | 1998 | 0.2891 Mt | 2017 | 1.2306 Mt |
| 1980 | 1.3758 Mt | 1999 | 0.3038 Mt | 2018 | 0.6419 Mt |
| 1981 | 1.2175 Mt | 2000 | 0.3992 Mt | 2019 | 1.0095 Mt |
| 1982 | 1.117 Mt | 2001 | 0.4602 Mt | 2020 | 0.8348 Mt |
| 1983 | 1.2305 Mt | 2002 | 0.4656 Mt | 2021 | 0.8408 Mt |
| 1984 | 1.0926 Mt | 2003 | 0.5042 Mt | 2022 | 0.8686 Mt |
| 1985 | 1.0966 Mt | 2004 | 0.5452 Mt | 2023 | 0.8395 Mt |
| 1986 | 0.8531 Mt | 2005 | 0.6812 Mt | 2024 | 0.8671 Mt |
| 1987 | 0.8929 Mt | 2006 | 0.717 Mt | | |
| 1988 | 1.0728 Mt | 2007 | 0.6693 Mt | | |
Show data table
| 1970 | 0.66 t | 1989 | 0.32 t | 2008 | 0.15 t |
| 1971 | 0.64 t | 1990 | 0.17 t | 2009 | 0.13 t |
| 1972 | 0.63 t | 1991 | 0.13 t | 2010 | 0.2 t |
| 1973 | 0.63 t | 1992 | 0.11 t | 2011 | 0.21 t |
| 1974 | 0.66 t | 1993 | 0.12 t | 2012 | 0.22 t |
| 1975 | 0.67 t | 1994 | 0.12 t | 2013 | 0.2 t |
| 1976 | 0.68 t | 1995 | 0.12 t | 2014 | 0.26 t |
| 1977 | 0.68 t | 1996 | 0.12 t | 2015 | 0.26 t |
| 1978 | 0.68 t | 1997 | 0.11 t | 2016 | 0.29 t |
| 1979 | 0.77 t | 1998 | 0.11 t | 2017 | 0.25 t |
| 1980 | 0.71 t | 1999 | 0.11 t | 2018 | 0.13 t |
| 1981 | 0.61 t | 2000 | 0.14 t | 2019 | 0.2 t |
| 1982 | 0.55 t | 2001 | 0.15 t | 2020 | 0.16 t |
| 1983 | 0.58 t | 2002 | 0.15 t | 2021 | 0.16 t |
| 1984 | 0.5 t | 2003 | 0.16 t | 2022 | 0.16 t |
| 1985 | 0.49 t | 2004 | 0.17 t | 2023 | 0.15 t |
| 1986 | 0.37 t | 2005 | 0.21 t | 2024 | 0.15 t |
| 1987 | 0.38 t | 2006 | 0.21 t | | |
| 1988 | 0.44 t | 2007 | 0.18 t | | |