How many years ago did the speakers last see each other?

M: Lucy, what a nice surprise! I didn’t expect to see you here.
W: Hi, Gabriel. Actually, I didn’t think I would be able to come here, but my business trip has been pushed back to another day. I am so happy that I can make it to our ten- year reunion.(46)It’s so amazing to be back on campus. Many things have changed.
M:(44)Can you believe it’s been ten years since we’ve seen each other? Remember the time you and I did a presentation together and made a lot of mistakes?(46)But Professor Williams gave us A plus anyway.
W:(45)How can I forget! That’s one of my best memories of my university days.