A stem leaf plot is kinda like a frequency table and a histogram, let's start with that.
We'll group the data by tens, by leading digit, shown in bold. For each day we write the ones digit after the leading digit.
5 613
6 3
7 42742685
8 66814957
9 4021
Now we just count of the days for the frequency table,
range count
50-59 3
60-69 1
70-79 8
80-89 8
90-99 4
Now we have to make a histogram; the stem leaf table pretty much is one; let's replace the data by *
50-59 ***
60-69 *
70-79 ********
80-89 ********
90-99 ****