I also think there is a wide range. Both of my boys were down to only one nap a day by 14 months. Our day for my first was wake at 7:30-8, nap at 1-3, bed at 7:30. Our second LO (now 18 months but on the same routine since 14 months) wake 7-7:30, nap 12 - 2-2:30, bed at 7. I guess the A time for my kids were both around 5 hours in am and 3.5-4 hours pm. My second child seems to need just a little more sleep.
I hope this helps.