What is the cumulative percentage of completion in 2010?

in thousands Construction costs incurred during the year construction costs incurred prior years cumulative actual construction costs estimated costs to complete at end of year total estimated and actual construction costs total estimated revenue billings made during the year cash collections during the year 2010 500 0 500 1,500 2,000 4000 1250 1000 2011 800 500 1300 700 2,000 4000 1250 1000 2012 900 1,300 2200 0 2,200 4000 1500 2000