Newsletter Success amount vs Clicked amount, difference?

Hey there,

I'm a beginner using Marketo and I realized that one of our newsletter has a different amount for success and for clicked (I'll attach snippet). Is this just a discrepancies in numbers or is success measuring something else vs clicked? I know we have triggers to measure measure "clicks" and then changing the newsletter program status to "clicked", so that's why I'm a bit confused with the difference in the numbers.

I apologize if this is a simple question, I tried to search for some information but could not find much. Thanks in advance