8. Other operating expenses Other operating expenses include insurance, office accommodation and inventory costs, auditor’s fees, marketing costs, rental and lease costs for operating assets and additions to provisions. Auditor’s fees(in millions of euros)20162015*)Statutory audits2.62.3 Other assurance engagements0.40.4 Tax advisory services- - Other services- - Total3.02.7 *The 2015 comparative figure has been adjusted for charges in relation to additional work in 2015, agreed after the issue of the financial statements 2015.The auditor’s fees comprise the fees both for services in the Netherlands and those for the network abroad.The fees for the Dutch audit firm for the year amounted to € 2.5 million (2015: € 2.3 million).