What would be an appropriate discount rate for this company given that the stock market has returned roughly 8-10% annually for the past thirty years?

Data for this Date Range Aug. 31, 2018 May 31, 2018 Feb. 28, 2018 Nov. 30, 2017 Aug. 31,2017 May 31.2017 Feb.28, 2017 Nov. 30,2016 Aug. 31, 2016 May 31, 2016 Feb. 29, 2016 Nov.30, 2015 Aug. 31, 2015 May 31, 201 Feb. 28, 2015 Nov. 30,2014 Aug. 31, 2014 May 31,2014 Feb. 28, 2014 Nov. 30, 2013 Aug. 31,2013 May 31,2013 Feb. 28, 2013 Nov. 30, 2012 Aug. 31, 2012 May 31,2012 Feb. 29, 2012 Nov.30,2011 Aug. 31, 2011 STZ Free Cash Flow (SMM USD)TTM 1,045 873.8 727.3 776.6 788.6 768.7 690.4 622.9 522.4 730.6 361.6 268.3 602.7 700.6 398.7 494.2 465.8 570.4 572.2 745.9 530.6 494.7 525.5 Feb.28, 2011 Nov. 30, 2010 Aug. 31, 2010 May 31,2010 Feb. 28,2010 Nov. 30, 2009 Aug. 31,2009 May 31, 2009 Feb. 28, 2009 Nov. 30, 2008 Aug. 31, 2008 May 31, 2008 Feb. 29, 2008 Nov. 30,2007 Aug. 31, 2007 May 31, 2007 Feb. 28, 2007 Nov. 30,2006 Aug. 31, 2006 May 31, 2006 242.5 285.8 331.3 378.3 438.5 370.1 273.6 56.9 170.7 235.81 Data for this Date Range Aug. 31, 2018 May 31, 2018 Feb. 28, 2018 Nov. 30, 2017 Aug. 31,2017 May 31.2017 Feb.28, 2017 Nov. 30,2016 Aug. 31, 2016 May 31, 2016 Feb. 29, 2016 Nov.30, 2015 Aug. 31, 2015 May 31, 201 Feb. 28, 2015 Nov. 30,2014 Aug. 31, 2014 May 31,2014 Feb. 28, 2014 Nov. 30, 2013 Aug. 31,2013 May 31,2013 Feb. 28, 2013 Nov. 30, 2012 Aug. 31, 2012 May 31,2012 Feb. 29, 2012 Nov.30,2011 Aug. 31, 2011 STZ Free Cash Flow (SMM USD)TTM 1,045 873.8 727.3 776.6 788.6 768.7 690.4 622.9 522.4 730.6 361.6 268.3 602.7 700.6 398.7 494.2 465.8 570.4 572.2 745.9 530.6 494.7 525.5 Feb.28, 2011 Nov. 30, 2010 Aug. 31, 2010 May 31,2010 Feb. 28,2010 Nov. 30, 2009 Aug. 31,2009 May 31, 2009 Feb. 28, 2009 Nov. 30, 2008 Aug. 31, 2008 May 31, 2008 Feb. 29, 2008 Nov. 30,2007 Aug. 31, 2007 May 31, 2007 Feb. 28, 2007 Nov. 30,2006 Aug. 31, 2006 May 31, 2006 242.5 285.8 331.3 378.3 438.5 370.1 273.6 56.9 170.7 235.81