What's the most important stat for a Goalkeeper?

Paul & Martin discuss what measurable statistic is the best to use to asses a goalkeepers performance.
From Clean Sheets to Expected Goals Conceded - What can and can't you measure?
It might be safe to say Martin isn't a 'StatMan'
What goals should Goalkeepers set themselves stats wise?

[@Terdacol]

First :)

[@Lightingboiiii]

69th