Wow, only 4 times in 4 years. That's good stats. Come over here to the tropics, and it'll be a little different. I've had 3 in the last 8 months and a few more were very close! ie runway in sight just above minima. 99% of the time it's due to the visibility in torrential rain. Of course if from tower observations it is below our approach minima, we won't even bother to attempt an approach. Sometimes it can change from bad to worse all of a sudden when on finals. One other time it was because aircraft was still on the runway, taking it's own sweet time to vacate after missing the first intersection.
It happens, but as WWW says, largely a non-event flown to procedures. Unless it's during a Simulator LOFT or Base Check...then that's when it's a big song an dance with plenty to do to keep you occupied!
