Year

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

δ × 10 4

3.3

3.0

3.0

2.9

3.3

2.5

2.6

2.7

2.8

3.0

k ^

9.4

9.6

10.5

11.1

13.6

11.9

12.5

13.7

14.7

15.8

k max

5430

6430

7684

8416

11,179

9838

10,682

11,739

18,110

13,725

k min P L

23

8

44

30

16

15

17

17

14

14

α

2.12 ± 0.03

2.13 ± 0.01

2.08 ± 0.03

2.07 ± 0.03

2.20 ± 0.02

2.10 ± 0.01

2.10 ± 0.02

2.11 ± 0.01

2.10 ± 0.01

2.14 ± 0.01

p ± 0.01

0.67

0.04

0.60

0.93

0

0

0

0

0

0