20 instances from 3 years 2018 - 3 instances Jan Feb Mar Apr May Jun 21 24 27 Jul Aug Sep Oct Nov Dec 2017 - 4 instances Jan 8 Feb Mar Apr May Jun 23 Jul Aug Sep Oct 4 Nov Dec 29 2016 - 13 instances Jan Feb 18 Mar Apr May Jun 21 22 Jul Aug Sep 20 4 Sep 20, 2016 4 instances 17:15:10 17:41:41 22:25:31 22:44:01 Oct 1 2 4 3 Oct 4, 2016 3 instances 18:12:52 18:40:05 21:39:36 Nov Dec 30