A surprising useful number to remember is the number of seconds in a year: you can remember it as 30 million, or (if you’re so inclined) 10 million times pi, though the more accurate number is about 31.5 million (on average). From there it follows that there are about half a million minutes a year.
So when you hear that “every X seconds, Y happens” (e.g., “an American is the victim of a violent crime”), you can translate that into a raw number. I find the “every X seconds, Y happens” locution not very helpful in such situations, but people often use it; when they do, the 30 million number helps you translate it into something more understandable.