2. Percentage of completion

2. PERCENTAGE OF COMPLETION
       
EUR million   31 Dec 2016 31 Dec 2015
Income statement related items      
Contract sales recognized under percentage of completion accounting during the financial year   113.3 126.7
Other sales   1 379.3 1 333.4
Net sales   1 492.6 1 460.1
       
Accumulated amount recognized from percentage of completion based contract sales since inception for contracts open at the end of the financial year   175.5 193.0
       
Balance sheet related items      
Accounts receivables related to percentage of completion based contract sales   27.4 30.9
Unbilled related to percentage of completion based contract sales less recognized losses   20.3 13.8
Gross amounts due from customers related to work in progress contracts   47.7 44.7
       
Unearned related to percentage of completion based contract sales less recognized losses   15.2 13.9