Compared with patients who avoided these painkillers, those who took an NSAID had a 2.4-fold higher risk of a major bleed and those who took aspirin had a 1.5-fold higher risk. Even though [this warning about major bleeds with NSAIDS or aspirin] is on the warfarin label. . .
5 years. A decade means 10 years, so to find out how many years are  in half of a decade you would simply divide 10 by 2, which is 5.
A millennium is a period of time equal to one thousand years. There are two main viewpoints about naming millennia and there was a popular debate leading up to the celebrations of the year 2000 as to whether 2000 was the beginning of a new millennium.