How do you estimate Beta for the following 2 sub periods.

Period 1: June 2012 to July 2014 31/03/2012 30/04/2012 31/05/2012 30/06/2012 31/07/2012 31/08/2012 30/09/2012 31/10/2012 30/11/2012 31/12/2012 31/01/2013 28/02/2013 31/03/2013 30/04/2013 31/05/2013 30/06/2013 31/07/2013 31/08/2013 30/09/2013 31/10/2013 30/11/2013 31/12/2013 31/01/2014 28/02/2014 31/03/2014 30/04/2014 31/05/2014 30/06/2014 Adj Close null 4133.700195 4135.5 4289.399902 4339 4406.299805 4535.399902 4518 4664.600098 4901 5120.399902 4979.899902 5168.600098 4914 4775.399902 5035.700195 5125.299805 5217.700195 5420.299805 5314.299805 5353.100098 5205.100098 5415.399902 5403 5470.799805 5473.799805 5382 5623.100098