Quarter Millions of US Dollars 2008-01-01 14 2008-04-01 40 2008-07-01 50 2008-10-01 50 2009-01-01 50 2009-04-01 24 2009-07-01 24 2009-10-01 24 2010-01-01 24 2010-04-01 24 2010-07-01 24 2010-10-01 24 2011-01-01 24 2011-04-01 24 2011-07-01 14 2011-10-01 14 2012-01-01 514 2012-04-01 514 2012-07-01 500 2012-10-01 500 2013-01-01 1500 2013-04-01 1500 2013-07-01 1500 2013-10-01 1500 2014-01-01 2750 2014-04-01 3255 2014-07-01 3265 2014-10-01 3315 2015-01-01 4183 2015-04-01 4182 2015-07-01 4182 2015-10-01 4132 2016-01-01 4014 2016-04-01 4000 2016-07-01 4002 2016-10-01 4002 2017-01-01 3502 2017-04-01 3500 2017-07-01 3500 2017-10-01 3500 2018-01-01 4000 2018-04-01 4000