You can fix that via the simple expedient of adding a numeric picture switch to the mergefield:
1. Select the mergefield and press Shift-F9. You should see something like { MERGEFIELD Data }
2. Add a '\# 0' numeric picture switch to the mergefield so you get { MERGEFIELD Data \# 0}
3. Press F9 to update the display.
Done.

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