Falling into you

How common is it to see people fall? Once a year? Once a month? Once a week? Or once a day?
I must be lucky to have witnessed 3 fall within 3-4 days then?

Fall 1. A young lady was running on the opposite side of the street and boom she fell. Stood up quite quickly and did the routinely look-around.
Fall 2. My friend was walking down the steps behind me and boom he was sitting down, "resting".
Fall 3. A guy at work walking in the opposite direction of me talking to his friends, looking at me and boom he hit the trash can and fell on it.

If I'd had captured those moment somehow then I could post them up on youtube =P