"A report released last week by the Cato Institute measured the risk to Americans posed by refugees. The report found that an American’s chances of being killed by a refugee in a terrorist attack in any given year are 1 in 3.64 billion. America’s murder rate — at 4.5 per 100,000 capita — is about 163,800 times higher.
As the Washington Post’s Philip Bump points out, adhering to Trump’s analogy, a bowl with three deadly Skittles (refugees) in it would need to contain 10.93 billion Skittles. Bump calculated this to be the equivalent of 1.5 Olympic-size swimming pools full of the candy. This would equate to a bowl of Skittles roughly 246 feet long, 123 feet high, and 9 feet deep."