I have a light right foot and an Nx300h Premier. The car started out returning an indicated 37 - 38 mpg in December. With 7000 miles on the clock it is now showing 41 mpg over the last 1500 miles. Car is driven in eco mode and I tend to stay about 70 on motorways. Consumption gets better by about 5% in warmer weather. I have checked these figures by filling the tank to the top from time to time.
On my previous car, Rx450h I was getting about 34mpg. Hope this helps but I am certain that driving style has a big effect.