Tracking % Changes Over Time

edited 12/09/19 in Smartsheet Basics

I have a master sheet (linked to many other, scope-specific QC sheets) that calculates % completion per task.

Each row is for a different task, and each task has their own amount of steps. This information is all linked & calculated from the scope-specific sheets. Column 1 shows "# of steps completed to date", column 2 shows "Total Steps", and column 3 calculates "% completion" from columns 1 and 2.  

I would like to track (and graph) the % completed over time, preferably by week. This would require tracking the changes in column 3 on a weekly basis. From what I can tell, I would need to add another sheet to track this & graph from. 

Does anyone know of an automated way I can export that column & have it added as a "new column" on a new sheet? It seems that Zapier only works with row-based triggers.