From 98% to 91% battery life on sleep. Is this normal?

I recently bought a Macbook Air and last night, I charged it and unplugged at 98%. Closed the lid, which means it was on sleep mode. After 20 hours, I opened it and saw that my battery is at 91%. I didn't use it the whole day, I don't use keyboard backlights, and the only thing open before I closed the lid was Chrome.

Is the 98% to 91% even while on sleep normal?

Is there any way I can save up battery?

I have these settings in my Energy Saver:

Put hard disk to sleep when possible (checked)

slightly dim display when on battery power (checked)

enable power nap (unchecked)

Thanks!