Quarter Millions of US Dollars 1967-04-01 25 1967-07-01 25 1967-10-01 25 1968-01-01 25 1968-04-01 25 1968-07-01 25 1968-10-01 25 1969-01-01 25 1969-04-01 25 1969-07-01 25 1969-10-01 25 1970-01-01 25 1970-04-01 25 1970-07-01 25 1970-10-01 25 1971-01-01 39 1971-04-01 39 1971-07-01 39 1971-10-01 39 1972-01-01 84 1972-04-01 106 1972-07-01 205 1972-10-01 284 1973-01-01 330 1973-04-01 373 1973-07-01 370 1973-10-01 350 1974-01-01 357 1974-04-01 359 1974-07-01 356 1974-10-01 394 1975-01-01 424 1975-04-01 425 1975-07-01 473 1975-10-01 604 1976-01-01 661 1976-04-01 741 1976-07-01 980 1976-10-01 1057 1977-01-01 1166 1977-04-01 1227 1977-07-01 1283 1977-10-01 1535 1978-01-01 1791 1978-04-01 1874 1978-07-01 2299 1978-10-01 2412 1979-01-01 2494 1979-04-01 2605 1979-07-01 2781 1979-10-01 2722 1980-01-01 2571 1980-04-01 3135 1980-07-01 3323 1980-10-01 3268 1981-01-01 3279 1981-04-01 3042 1981-07-01 3234 1981-10-01 3485 1982-01-01 3548 1982-04-01 3545 1982-07-01 3333 1982-10-01 3717 1983-01-01 3710 1983-04-01 3862 1983-07-01 3826 1983-10-01 4597 1984-01-01 5608 1984-04-01 5710 1984-07-01 6654 1984-10-01 7001 1985-01-01 7267 1985-04-01 8000 1985-07-01 7968 1985-10-01 7869 1986-01-01 7945 1986-04-01 8915 1986-07-01 11839 1986-10-01 13577 1987-01-01 16741 1987-04-01 16582 1987-07-01 16720 1987-10-01 18168 1988-01-01 17622 1988-04-01 17267 1988-07-01 16886 1988-10-01 16239 1989-01-01 15190 1989-04-01 14739 1989-07-01 14780 1989-10-01 15773 1990-01-01 16881 1990-04-01 16623 1990-07-01 18180 1990-10-01 18197 1991-01-01 16391 1991-04-01 15842 1991-07-01 15609 1991-10-01 14504 1992-01-01 11061 1992-04-01 11193 1992-07-01 11683 1992-10-01 11432 1993-01-01 12834 1993-04-01 14074 1993-07-01 20957 1993-10-01 20873 1994-01-01 20510 1994-04-01 19769 1994-07-01 19914 1994-10-01 19456 1995-01-01 19876 1995-04-01 19889 1995-07-01 18813 1995-10-01 18502 1996-01-01 17619 1996-04-01 17455 1996-07-01 17188 1996-10-01 17463 1997-01-01 17419 1997-04-01 17512 1997-07-01 17125 1997-10-01 16124 1998-01-01 15029 1998-04-01 13978 1998-07-01 14029 1998-10-01 13369 1999-01-01 12747 1999-04-01 12233 1999-07-01 13366 1999-10-01 12175 2000-01-01 10905 2000-04-01 10687 2000-07-01 10427 2000-10-01 10798 2001-01-01 10114 2001-04-01 10312 2001-07-01 10223 2001-10-01 9443 2002-01-01 8882 2002-04-01 8835 2002-07-01 8773 2002-10-01 7742 2003-01-01 7389 2003-04-01 9464 2003-07-01 8685 2003-10-01 8229 2004-01-01 7826 2004-04-01 7332 2004-07-01 6923 2004-10-01 6942 2005-01-01 9044 2005-04-01 7894 2005-07-01 7191 2005-10-01 7063 2006-01-01 7153 2006-04-01 7402 2006-07-01 7370 2006-10-01 6567 2007-01-01 6588 2007-04-01 6652 2007-07-01 6859 2007-10-01 6926 2008-01-01 7330 2008-04-01 7306 2008-07-01 6066 2008-10-01 12101 2009-01-01 16143 2009-04-01 22386 2009-07-01 22397 2009-10-01 21909 2010-01-01 21483 2010-04-01 18742 2010-07-01 19664 2010-10-01 19053 2011-01-01 25658 2011-04-01 26459 2011-07-01 28274 2011-10-01 21953 2012-01-01 19592 2012-04-01 17371 2012-07-01 17501 2012-10-01 17550 2013-01-01 12067 2013-04-01 13759 2013-07-01 14080 2013-10-01 14203 2014-01-01 12666 2014-04-01 12154 2014-07-01 11447 2014-10-01 11115 2015-01-01 10369 2015-04-01 9290 2015-07-01 8882 2015-10-01 7146 2016-01-01 4436 2016-04-01 3083 2016-07-01 2759 2016-10-01 2810