Fill final page with blank lines

I have written a report to act as a class register for music teachers. The data displays fine, but I have been asked to fill the final page of each report with blank lines so the details of any unexpected students can be added. I could add a fixed number of blank lines but this may push onto a new page. The only other possibility I could think of was to work out the number of records that would fit on a page, add five details sections with blank lines and suppress if the rownumber is greater than the limit. This sounds messy though - is there a slicker way to do this?