Are you counting sharts? Like you try to fart, and a little bit of solid comes out? If that's the case, it was within the last four or five months.
Or what about when you're first getting diarrhea but you're not sure yet, so you try to toot, but it's a squirt instead? That's happened in the last year or two also. That's especially annoying because it shoots straight through the underwear, pants, and onto the seat, so it requires cleaning three things.
If you're talking a full load, then I have no idea. I do remember when I was still in diapers around age 2 or 3, I sat down and felt a squish, and only then did I realize that I had shat my diaper; I hadn't felt any indication that I had needed to poop or that I had been in the process of pooping. It was just there.