[33] Contract balances

Of the contract assets of €119.3 million (31 December 2017: €100.3 million), €114.7 million was attributable to project business contracts with a net credit balance due from customers (31 December 2017: €100.3 million) and €4.5 million to other contract assets (31 December 2017: €0.0 million). Of the contract assets recognised as at 1 January 2018, €88.1 million was billed in 2018 (2017: €61.3 million). By contrast, contract assets rose year on year because the goods and services provided by the KION Group before the agreed payment deadlines increased by €213.8 million in the reporting year (2017: €177.7 million). As had been the case in the previous year, no write-downs were recognised on contract assets.

Of the contract liabilities, €498.7 million was attributable to project business contracts with a net debit balance due to customers (31 December 2017: €255.9 million) and €71.4 million to prepayments received from customers (31 December 2017: €68.5 million). Contract liabilities are recognised as revenue as soon as the contractual goods and services have been provided. The revenue recognised in the reporting period that was included in the contract liability balance at the beginning of the period amounted to €292.6 million (2017: €265.7 million). Contract liabilities rose year on year, in particular because the prepayments received from customers increased by €221.8 million to €558.3 million in the reporting year (2017: €336.5 million).