Well, goodness, that's very specific. Ha!
We are a family of four who gives about 8% of our gross to our church, so maybe our church can qualify as a third child, finance wise?
We also have closer to 100K in income, but the extra 10K is rental income that all goes towards paying that mortgage on the rental house so it's not really extra income, if that makes sense.
Anyways, we save similar amounts to you, about 11K, in order to max out IRAs. However, if I were not in school, we would easily be able to save 20K. If we weren't also trying to pay down the mortgage, we'd save closer to 25K a year. If my husband didn't take sitar lessons, it would be closer to 28K, and if did cheaper vacations, it would be 31K.
It depends on your situation, but I would hope on a 90K income you could save at least 20K a year. We don't, because of school costs, mainly.