How to rescale an unevenly-sampled wave to one-minute intervals?

I've got some data that was sampled at *roughly* 20 second intervals, but always coming in at odd times like hh:mm:20, hh:mm:43, etc. I would like to resample this data so that I get one data point every minute, on the minute, like hh:00:00, hh:01:00, etc. I am somewhat new to Igor. What's a good way to accomplish this?

I've attached the time series and its associated data wave. Any help is appreciated!