Still pertinent!
My older two (17 and 13) stopped believing around 8 or so. 2nd or 3rd grade. They are very logical children lol and figured out early that the "story" was impossible by scientific standards.
DS11 (12 in Feb), when pressed last year by me, when he was 10 and in 5th grade:
ME: So what do you know about Santa?
HIM: (shrug) I guess he is the one who brings presents
ME: How do you think he gets millions of toys to kids all around the world in one night?
HIM: (looked at me for a minute, then sighs) Honestly, as long as I get presents under the tree on Christmas morning, I don't really care how they get there
LOL
This year, he confessed that he has known the truth since he was about 9 but since he was the youngest, he was scared to tell me and ruin Christmas for his older siblings lol. We stopped putting money under his pillow when he found out about the tooth fairy and he was worried we would stop giving Christmas presents, too, once he had figured it out.
BUT....we are worried about our Nephew whom we have recently taken guardianship of, also in 6th grade and 11 years old. He truly does believe in Santa, and even when gently pressed with logical thinking like "how can he get presents to millions of kids in one night", his answer was "power boosters", which told me that he still wasn't able to connect the logic of Santa with the myth. He is immature in many ways compared to other 11 year old 6th graders - he still plays with Spiderman figures, and loves Pokemon, doesn't like to bathe or comb his hair, etc - and we have reason to believe he may have some developmental delays as well that we are starting the testing process on in the new year. We think that he just hasn't hit the level of cognitive thinking yet where he can analyze abstract concepts or deductive reasoning. He seems to us to be more of a 8-9 year old level in pretty much every area of development, so it only makes sense to us that he still believes in Santa. The problem is, he is in 6th grade. He has said to us that some kids still believe and some don't, but the kids who don't will still get presents anyway, and we didn't have the heart to tell him any different. It will be interesting to see how he develops over the next year.