List <IEnumerable <CostAverageItem> > GetCostAverageItems()
{
return(new List <IEnumerable <CostAverageItem> >()
{
QueriesHelper.GetCostAverageItems(unitOfWork.OrderItems, Period.ThisYear),
QueriesHelper.GetCostAverageItems(unitOfWork.OrderItems, Period.ThisMonth),
QueriesHelper.GetCostAverageItems(unitOfWork.OrderItems, Period.FixedDate, LastOrderDate(unitOfWork))
});
}