From crew resources, sorry about the formatting. AE's since 2012
For the 5 years from 2102 through 2016 30 total or 6 per year average.
Year
Month
2012
March
2012
August
2012
October
2013
March
2013
June
2013
July
2013
September
2013
October
2013
December
2014
January
2014
February
2014
March
2014
April
2014
May
2014
July
2014
August
2014
September
2014
November
2015
January
2015
February
2015
April
2015
August
2015
October
2015
November
2016
January
2016
March
2016
May
2016
July
2016
October
2016
December
2017
February
2017
May