DIF_001 3991,3992c3991,3992 DIF_002 < Unique ID, for keeping track of analyses: 302TYRAE DIF_003 < Compiled / run: Apr 11 2014 / Mar 2 2019 (76 seconds) (VitalPro for Win32) DIF_004 --- DIF_005 > Unique ID, for keeping track of analyses: 9312qgbq (9312QGBQ) DIF_006 > Compiled / run: Sep 20 2015 / Mar 12 2019 (58 s) (VitalPro for Win32) DIF_007 3995d3994 DIF_008 < http://www.cdc.gov/nchs/data/9manual.pdf