Year Number 1985 5.762604105153199 1986 11.366262613271726 1987 55.206261613851126 1988 3.417615019927427 1989 4.14035825174849 1990 19.6706147833331 1991 1.2485771488289115 1992 1.2248005477295543 1993 23.798126093546795 1994 35.812079677825835 1995 567.4621416348972 1996 62.475384696896555 1997 6.266227024590175 1998 43.99399800076866 1999 17.027195918383335 2000 2.92447042630336 2001 1.1827960210727138 2002 1.5369568641491258 2003 1.1012892230538462 2004 0.4051341380597571 2005 0.24972974167674886 2006 0.1947187909987469 2007 0.23778537042022388 2008 0.28864172394644194 2009 0.4623839165886533 2010 0.7821092694139407 2011 0.6309419315187416 2012 0.6454614138114879 2013 0.6823589585786518 2014 0.9022659708107178 2015 1.6898211282759998 2016 25.755786596219366 2017 34.13876003037721 2018 32.93117844268393 2019 34.706203552462995 2020 22.50488140177608 2021 31.894443905285463 2022 1.0505240203261197 2023 1.1128316954196784