Jorgansen Lighting, Incorporated, manufactures heavy$-$duty street lighting systems for municipalities. The company uses variable costing for internal management reports and absorption costing for external reports. The company provided the following data:

$\backslash$table$[[,$Year $1,$Year $2,$Year $3],[$Inventories:$,,,],[$Beginning $($units$),200,170,180],[$Ending $($units$),170,180,220],[$Variable costing net operating income,$$1,080,400,$$$1,032,400,$$$996,400$