Running total as a percentage

Hello,
I have a group of employees that must complete training. They are listed in a column. As each employee completes the training I will enter an "x" in the column next to their name. At the bottom of the column I want to show a running total displayed as a percentage of employees that have completed the training...so I need to display the total of nonblank cells in a column as a percentage?? Very simple but I haven't worked with Excel much recently. Help!