Forecast total sales each year by building up the sales forecasts from the store level. To do this, you need to forecast sales for each store cohort using both aggregate furniture sales growth from Exhibit $2$ combined with store$-$level growth from Exhibit $10.$ Use the averages by cohort year to construct the forecasts. For example, to forecast Sales for the $2011$ cohort of stores in $2013,$ we do the following:

Sales$2013=$ Sales$2012(1+$ gagg,$2013)(1+$ gstore,$+2)=3,353\mathrm{.}7(1+0\mathrm{.}03)(1+0\mathrm{.}702)$

$=5,879$

where gagg,$2013$ is the furniture sales growth rate in $2013($Exhibit $2)$ and gstore,$+2$ is the average store$-$level revenue growth rate for a store in its second year $($Exhibits $8$ & $10).$