It looks like the sample and population means are both 50, but assuming the distribution is normal, by the empirical rule (which states that 95% of the data will be within 2 standard deviations of the mean), we see the standard deviation for the sample means must be about 0.325. And so the shaded portion would appear to perhaps be the data within roughly 1.23 standard deviations above the mean.

Beyond that, it's impossible to tell.