Are you sure imac sales are increasing?
Apple normally reports sales by product line rather than by model within a product line and Mac sales — that is all Macs including Mac Mini, MacBook, MacBook Air, MacBook Pro, iMac, and Mac Pro — have shown a small but consistent increase in sales almost every quarter. At the same time the general computer market — which includes all PC manufacturers as well as Apple — has seen a slow but steady decrease in sales. The few times Apple has released sales figures for a specific model line the focus has been on their laptops — MacBook, MacBook Air, and MacBook Pro — and it would appear they are doing the heavy lifting for the rest of the Mac product line, not the iMac.
