How to create a counter that increments every minute?

I'm trying to create a field that increments every minute as long as Status=Open.  Here's what I've done so far:

- Created a integer field with a default value of 0.

- Created a workflow rule where the workflow rule condition is [<Status>] = "Open" and the Trigger Event is "When new record is saved".

     - There is a "Wait" action where the period is set to 1 minute.  The "Reevaluate Rule Conditions After Wait" checkbox is checked.

     - There is a "Field Update" action where the value is "=[<counter>] + 1".  The "Active" and "Overwrite Existing Values" checkboxes are marked.

The field isnt incrementing.  Am I going about this the wrong way?