Excel 2007 : Average if multiple criteria and contains

I am trying to find the average units sold on one sheet (sht1) of the data on a second sheet(sht2). Does anyone know how i could do this by year="2000" and Car="Contains 2DR"?

I am sort of a novice with excel and do not fully understand the if functions. So any explanation or help would be greatly appreciated.

Sht1:
Year 2000 2Drs Avg Sold:
Year 2000 4Drs Avg Sold:

Sht2:
Car Year Units Sold
Ford Focus 2dr 2000 2
Chrystler 300 4dr 2000 3
Saturn ion 2dr 2000 2
Honda Civic 2dr 2004 1

Thanks!