Nature of Disturbance/Year

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

Partial Collapse

15

20

20

06

08

02

07

02

06

02

Total Collapse

25

19

22

13

16

22

02

10

04

12

Total System Collapse

40

39

42

19

24

24

09

12

10

14