When I requested an Uber for pickup from the Seattle airport's rideshare stop I saw a line of about 20 Priuses all in a row. In LA, from my sample size of several dozen Uber rides, I've seen roughly 50% hybrids.

Sea-Tac airport has a minimum MPG requirement that vehicles must satisfy in order to do rideshare pickups, and it is high enough that almost all cars being used are Priuses.

I was going to say I saw the same thing for Lyft in SeaTac. So that makes sense.

In San Francisco it seems that about half of the ones I take are.