Suzuki Crossover

I have a 2008 Suzuki SX4 Crossover, and I was wondering how fast can I get the best gas mileage?

The Ministry of Transportation and EPA said that most vehicles optimize mpg on the highway at speeds of 55-60. Acceleration of judgments is where most gas is lost, so the city mileage can be less than 10 MPG highway in some vehicles. The higher the RPM more gas you burn, so the car with automatic transmission gears 5,6,7 MPG better then the older cars from 3 / 4 speed automatic.

engine likes high rpm
mine is 1.5lt prefers 35oo rev / min

according to this scheme the average consumer better speed \ fuel is 90-100 km / hr \ in 5th gear