7. Cash revenue on sales

 period ended 31/12/2013period ended 31/12/2012
Continued operations    
Revenues from product sales 2,122,758 2,113,878
Revenues from sales of goods and materials 589,649 460,959
Fees earned 16,274 21,456
Revenues from sales 2,728,681 2,596,293

Group companies hedge a portion of revenues from sales related to the risk of changes in commodity prices and exchange rate changes. In 2013, in connection with the realisation of the hedged item, the Group companies recognised the effective portion of derivatives used as hedging of future cash flows in revenues from sales in the amount of PLN 2,886,000, and respectively PLN 7,129,000 in 2012.