Quarter Millions of US Dollars 2011-01-01 100 2011-04-01 100 2011-07-01 100 2011-10-01 100 2012-01-01 100 2012-04-01 300 2012-07-01 300 2012-10-01 800 2013-01-01 1300 2013-04-01 1300 2013-07-01 1300 2013-10-01 1300 2014-01-01 1600 2014-04-01 1600 2014-07-01 2600 2014-10-01 2600 2015-01-01 2600 2015-04-01 2880 2015-07-01 2880 2015-10-01 2880 2016-01-01 3380 2016-04-01 3391 2016-07-01 3391 2016-10-01 2991 2017-01-01 3491 2017-04-01 3491 2017-07-01 3491 2017-10-01 3491 2018-01-01 4021 2018-04-01 4021