There is a limitation related to home office
expenses and the income that was earned while using the home office (reported
on Form 8829). This question is
gathering information to apply that limitation.
The question is asking what percentage of your business gross income is attributed to work
done in your home office.
For example: If all your work is done in
your home office, enter 100 (for 100%).
But if you figure that one-fourth of your income is made on the road (or
at other locations than your home office) and three-fourths of your income is
made from your home office, enter 75 (for 75%).