| 1月 | 2月 | 3月 | 4月 | 5月 | 6月 | 7月 | 8月 | 9月 | 10月 | 11月 | 12月 |
2006 | 4.4 | 4.2 | 5.8 | 5.6 | 9.3 | 11.7 | 17.2 | 8.6 | 10.9 | 11.5 | 6.1 | 4.7 |
2007 | 3.1 | 2.5 | 2.9 | 4.2 | 5.6 | 11.6 | 20.8 | 15.9 | 15.7 | 9.2 | 5.0 | 3.4 |
2008 | 2.8 | 2.6 | 3.5 | 5.2 | 6.3 | 9.2 | 13.9 | 17.3 | 16.1 | 9.7 | 9.6 | 3.7 |
2009 | 3.7 | 3.1 | 3.2 | 5.1 | 8.5 | 8.9 | 16.5 | 21.7 | 12.7 | 8.7 | 4.6 | 3.5 |
2010 | 2.9 | 2.2 | 2.8 | 3.9 | 6.5 | 10.9 | 22.7 | 15.9 | 14.6 | 9.2 | 4.8 | 3.7 |
2011 | 4.5 | 3.0 | 4.4 | 4.7 | 6.0 | 12.1 | 15.1 | 15.5 | 13.0 | 8.6 | 8.3 | 4.7 |
2012 | 3.0 | 2.5 | 2.9 | 3.5 | 7.7 | 8.9 | 25.3 | 13.8 | 14.9 | 9.8 | 4.3 | 3.5 |
2013 | 3.8 | 2.7 | 3.6 | 4.5 | 7.5 | 11.1 | 23.1 | 14.1 | 13.1 | 7.6 | 4.9 | 3.9 |
2014 | 2.9 | 2.6 | 3.3 | 5.6 | 5.7 | 9.3 | 16.1 | 16.3 | 19.1 | 9.9 | 5.4 | 3.9 |
2015 | 4.0 | 3.3 | 4.3 | 6.0 | 6.1 | 11.3 | 14.0 | 13.6 | 16.0 | 11.1 | 5.7 | 4.5 |
2016 | 4.1 | 3.7 | 4.7 | 6.5 | 8.8 | 13.1 | 17.7 | 12.5 | 9.3 | 9.0 | 6.5 | 4.1 |
2017 | 3.4 | 3.2 | 4.3 | 5.8 | 7.5 | 11.2 | 13.6 | 12.6 | 13.9 | 14.0 | 6.2 | 4.3 |
平均值 | 3.5 | 2.9 | 3.7 | 5.0 | 7.1 | 10.7 | 18.1 | 14.9 | 14.2 | 9.9 | 5.9 | 4.0 |