TABLE I -- SUMMARY OF TREASURY SECURITIES OUTSTANDING, JUNE 30, 2017 (Millions of dollars) Amount Outstanding Debt Held By the Public 14,366,186 Intragovernmental Holdings 5,478,368 Totals 19,844,554 JUNE 30, 2016 Debt Held By the Public 13,932,743 Intragovernmental Holdings 5,448,848 Totals 19,381,591
诚心请教,为什么19,844,554会比19,381,591减少1000亿?