I'm not sure if you want the following-dot, as in 33.33˙, or a macron.

For a dot, you could type the number, insert a space after it, type 02D9 followed by Alt-x, then remove the space.

For a macron, you could use a field coded as:
{EQ \s\up6(\f(,3))}
Compared to other field-based solutions, this one has the advantage of retaining the character sizes without increasing the line height. The ‘6’ in the formula controls the bar height.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]