To Place a Stacked Fraction with Auto-Stacking On

Select Text Styles (Drawing > Annotate > Text dialog launcher).
The Text Styles dialog opens.
On the General tab, turn on Fractions.
Select the Place Text tool.
The Text Editor window opens.
In the Text Editor window, key in the numerator, then a "/" or "#" character, then the denominator (for example 1/2) and then press <Space>.
The fraction is stacked according to the alignment last used in the toolbar’s Stacked Fractions button.

Note: Omitting the trailing white space will prevent auto-stacking, allowing you to manually create the stacked fraction via the Insert Stacked Fractions option in the right-click menu. The Insert Stacked fraction options allows you to change the fraction alignment.
Enter a data point to place the fraction.