Submitting empty cells

Data is submitted for January (leading period)-June (trailing period), but some cells are empty. After data is submitted, the periodic view is populated with periodic values (and empty cells). The year-to-date view is populated with leading zeroes and intermediate year-to-date values. In both views, the trailing period displays as empty cells.

Jan 2009 Feb 2009 Mar 2009 Apr 2009 May 2009 Jun 2009
Periodic Advertising
Travel Expense
Entertainment
Office Supplies
Training Expense
Year-to-date Advertising 1,500 3,500 5,500
Travel Expense
Entertainment 429
Office Supplies 530 956 1,223
Training Expense
Jan 2009 Feb 2009 Mar 2009 Apr 2009 May 2009 Jun 2009
Periodic Advertising 1,500 2,000 2,000
Travel Expense 2,590 2,470
Entertainment 429
Office Supplies 530 426 267
Training Expense
Year-to-date Advertising 1,500 3,500 3,500 3,500 5,500
Travel Expense 0 0 2,590 5,060 5,060
Entertainment 0 429 429 429 429
Office Supplies 530 530 956 1,223 1,223
Training Expense