The average daily insolation at the top of the atmosphere for Palatine is $\_\_\_\_\_\_\_\_\_\_\_\_$ kWh$/$m$2/$day$.($Need help? Refer to https:$//$www$.$skillsyouneed.com$/$num$/$averages$.$html or http:$//$bit$.$ly$/2$jVIMqM, if you would like to use Microsoft Excel$)$

$7\mathrm{.}64$

$6\mathrm{.}86$

$9\mathrm{.}50$

$4\mathrm{.}23$