Correct: 5/1200 is 0.00416666. However, when expressing it as a percentage, as you originally did, you multiply by 100 which moves the decimal place to the right two digits. I merely rounded to 0.42%, which is common, IMHO.
Nevertheless, we are in full agreement on the point itself: that the ratio is disheartening to the terrorists and the Democrats.
There were over 300 attacks back in January as people went to the polls......how many today?