pre_text: 9. Debtors The Directors consider that the carrying amount of trade and other debtors approximates their fair value. The Company has no significant concentration of credit risk attributable to its trade debtors as the exposure is spread over a large number of customers. Assets recognised from costs to obtain a contract relate to capitalised incremental costs to obtain a contract, being sales commissions arising on contracts with customers of more than one year in length. No assets were impaired or derecognised during the current year or prior year.
table: 2019 2018
table: Notes £ million £ million
table: Due within one year
table: Trade debtors 5.2 7.0
table: Owed by subsidiaries 13.7 9.6
table: Other debtors 0.2 0.7
table: Prepayments 0.4 0.6
table: Current tax asset 1.0 0.6
table: Deferred tax 13 – 1.3
table: Assets recognised from costs to obtain a contract 0.1 0.1
table: 20.6 19.9
table: Due after one year
table: Defined benefit pension plan surplus 3 8.8 2.0
question: Analyse this data from a financial earnings document. What was the change in the amount owed by subsidiaries?