Zeroing Out Data

So I sold my MacBook Pro yesterday. I'd reformatted the drive several times, but before reinstalling OS X, I decided to zero out the data. However, due to time constraints, I had to cancel the process near the end (when it says creating temporary image) due to time constraints. I did a quick reformat again (canceling the zero out made the drive temporarily unusable), installed OS X, and sold the computer.

Now, I'm wondering if any of my personal data will be accessible. It's not a huge deal as I hadn't been using that particular drive for almost 7 months now, and I'd done several reformats due to using it as an external. Also, I'm assuming a zero out is not reversible, and since the process almost finished, my drive was essentially all zero'd out anyway.

Anyone have any idea?

 

That's what I assumed. Thank you.

 

Ruh roh.. Hahaha.