City driving in the Yaris LB

[Yaris1]

I had been fairly conscience of how I'm driving my Yaris. So I'd driven on the feeder roads instead of the highway, and slowed down 5-10 mph while driving, (feeder roads are 45 and some are 50 mph posted signs) so I went a constant 40 mph. I figured my GPM on my last fill up. I ended up getting 36.87 gpm from driving mostly with coasting - engine on, occasional engine off. Twice with air cond. on, (I took my 73yo mother somewhere), and occasionally got on the freeway avg 55-60 mph. So I'd like to know if this is good. I am trying to get better gpm. But with average conditions, how does this result rate? BTW - My Yaris is an automatic trans.