These are levels for 5 & 10 10 μg/dL.

I don't remember the exact number, and can't find it in 10 minutes of googling, but before leaded gasoline was banned, the US average was much higher.

My brain wants to say around 40. I probably misremember, but it was in that range.

Which is to say that while the Flint situation is bad, it's much better than how every kid grew up when I was young.

Keep in mind that during the Flint water crisis everyone stopped drinking the lead contaminated water, so of course you aren't going to see a giant jump in the lead blood levels. That doesn't mean there wasn't a lot of lead in the water, and that doesn't mean it didn't have an impact on the residents.