Year	Number
1999	29.26037
2000	30.30531
2001	30.1753
2002	30.03338
2003	29.933
2004	30.12411
2005	32.24031
2006	31.2024
2007	31.53607
2008	32.6684
2009	32.32478
2010	30.24229
2011	30.84289
2012	30.82119
2013	30.16133
2014	29.36504
2015	29.18457
2016	29.21934
2017	35.1471
2018	29.65545