Year Number 1996 -1.14967966079712 1998 -1.10067796707153 2000 -1.15839385986328 2002 -1.21269547939301 2003 -1.03775930404663 2004 -0.703226566314697 2005 -0.903745830059052 2006 -0.379076540470123 2007 -0.245746776461601 2008 -0.222209960222244 2009 -0.280257672071457 2010 -0.158439069986343 2011 -0.0210469923913479 2012 -0.101652063429356 2013 -0.026739789173007 2014 -0.0522533990442753 2015 -0.146019995212555 2016 0.0137040875852108 2017 0.178770422935486 2018 0.0795299112796783 2019 0.0929242670536041 2020 0.274038255214691 2021 0.22790738940239 2022 0.232485979795456