How many plates ,of food and drink, does a rookie waiter/waitress spill on average per shift?

@RedDeerGuy1 Your question reminded me of one of my first days working as a car hop at a local drive in. On my tray were two large chocolate milkshakes. The wind was blowing hard and the milkshakes tipped over toward me on the tray and filling up the coin pockets of the belt I was wearing.

My first waitress job I was sixteen. I was eager to be pro, and got plates lined up both arms for a table of six.
When I got to the table a lady was trying to tell me something and I wasn’t getting it. I looked down where she pointed, and I had my left breast a bit over the edge of a plate, in somebody’s biscuits and gravy. I quickly placed the other plates around the table and promised the guy a new order right away. He said, nothing doing, it was probably the best gravy he was gonna get. Yikes I was embarrassed.
I dropped a few dishes in the kitchen, for which I was forgiven, but that was the worst!
They did leave a twenty dollar tip, and that was back in ‘79.