Quarter Millions of US Dollars 1975-04-01 12 1975-07-01 12 1975-10-01 31 1976-01-01 32 1976-04-01 56 1976-07-01 58 1976-10-01 70 1977-01-01 70 1977-04-01 70 1977-07-01 101 1977-10-01 105 1978-01-01 107 1978-04-01 107 1978-07-01 112 1978-10-01 113 1979-01-01 111 1979-04-01 112 1979-07-01 115 1979-10-01 115 1980-01-01 109 1980-04-01 114 1980-07-01 113 1980-10-01 109 1981-01-01 181 1981-04-01 177 1981-07-01 178 1981-10-01 181 1982-01-01 178 1982-04-01 214 1982-07-01 197 1982-10-01 177 1983-01-01 177 1983-04-01 152 1983-07-01 152 1983-10-01 140 1984-01-01 140 1984-04-01 140 1984-07-01 125 1984-10-01 125 1985-01-01 125 1985-04-01 125 1985-07-01 125 1985-10-01 200 1986-01-01 125 1986-04-01 125 1986-07-01 125 1986-10-01 125 1987-01-01 125 1987-04-01 200 1987-07-01 200 1987-10-01 275 1988-01-01 275 1988-04-01 275 1988-07-01 275 1988-10-01 275 1989-01-01 275 1989-04-01 275 1989-07-01 275 1989-10-01 275 1990-01-01 350 1990-04-01 350 1990-07-01 350 1990-10-01 350 1991-01-01 350 1991-04-01 370 1991-07-01 480 1991-10-01 480 1992-01-01 519 1992-04-01 469 1992-07-01 469 1992-10-01 394 1993-01-01 394 1993-04-01 394 1993-07-01 544 1993-10-01 484 1994-01-01 574 1994-04-01 626 1994-07-01 677 1994-10-01 727 1995-01-01 657 1995-04-01 659 1995-07-01 653 1995-10-01 502 1996-01-01 481 1996-04-01 730 1996-07-01 500 1996-10-01 741 1997-01-01 820 1997-04-01 965 1997-07-01 1559 1997-10-01 1583 1998-01-01 1548 1998-04-01 2041 1998-07-01 2113 1998-10-01 2138 1999-01-01 2182 1999-04-01 2624 1999-07-01 2633 1999-10-01 2588 2000-01-01 2628 2000-04-01 3515 2000-07-01 3860 2000-10-01 3938 2001-01-01 3640 2001-04-01 3362 2001-07-01 3368 2001-10-01 7098 2002-01-01 6994 2002-04-01 7075 2002-07-01 6399 2002-10-01 6424 2003-01-01 6634 2003-04-01 6695 2003-07-01 7113 2003-10-01 9864 2004-01-01 9957 2004-04-01 10365 2004-07-01 10364 2004-10-01 11377 2005-01-01 11434 2005-04-01 11463 2005-07-01 11634 2005-10-01 11422 2006-01-01 11450 2006-04-01 13168 2006-07-01 13267 2006-10-01 13707 2007-01-01 14191 2007-04-01 15431 2007-07-01 15651 2007-10-01 16820 2008-01-01 17620 2008-04-01 17671 2008-07-01 17821 2008-10-01 16973 2009-01-01 16563 2009-04-01 17379 2009-07-01 19142 2009-10-01 19290 2010-01-01 19535 2010-04-01 20424 2010-07-01 21113 2010-10-01 21496 2011-01-01 22246 2011-04-01 22128 2011-07-01 21827 2011-10-01 19973 2012-01-01 21606 2012-04-01 20901 2012-07-01 22545 2012-10-01 22883 2013-01-01 23974 2013-04-01 23331 2013-07-01 23669 2013-10-01 22920 2014-01-01 23867 2014-04-01 24599 2014-07-01 25075 2014-10-01 24533 2015-01-01 24677 2015-04-01 27038 2015-07-01 26104 2015-10-01 26246 2016-01-01 26038 2016-04-01 26020 2016-07-01 25749 2016-10-01 24901 2017-01-01 25234 2017-04-01 25265 2017-07-01 29154 2017-10-01 29856 2018-01-01 29558 2018-04-01 30792