Stochastic Consistency Test

Here are 5 jokes:

1. I told my computer I needed a break, and now it won’t stop sending me KitKat ads.
2. I tried to eat a clock once. It was very time-consuming.
3. Why don’t skeletons fight each other? They don’t have the guts.
4. I’m reading a book about anti-gravity. It’s impossible to put down.
5. I asked the librarian if the library had books on paranoia. She whispered, “They’re right behind you.”

How many are unique? 5 unique jokes.