They should be 42" -48" above finished floor. If you have a special tile pattern, the outlets should be adjusted up or down.

the outlets are being put in right now. the floor isn't in and backsplash is not picked out yet, which is why it is tough to tell if they are right.

According to my licensed electrician, the outlet height is not governed by code -- you want them high enough so there's no wetness danger, but not so high they impede your backsplash design. I wanted mine lower down so that they're hidden by the various appliances I plug into them.

One good thing to know is that it's honestly not very difficult to move an outlet box (depending on where the wall studs fall), so you will have some wiggle room later if you absolutely have to accommodate your tile design. I was DIY and moved them a few inches here and there so that they fit perfectly into the subway tile of my splash.
The bottom of mine land 3.25" above the countertop:

Here are mine, on either side of counter cat (one is lurking behind the coffeemaker):

My DH installed ours, and he put them high (bottom of plate is 11" above counter).

I think his reasoning was to make it easier to plug and unplug appliances. (Which it is). The funny (ironical) thing is that since he rewired the kitchen and added tons more capacity to our kitchen- we don't need to plug and unplug appliances anymore!!! :>) But when I do use occasional appliances like the popcorn popper/ breadmaker, etc. it is very easy to plug them in at the higher height.

He also wanted them all at an identical height- AND in line with our switch plates- so that's how he determined the exact height.