b'2018 2017(x US$1) Staatsolie SPCS Total Staatsolie SPCS TotalDefined benefit obligation as at January 1 (2,964,598) (17,941) (2,982,539) (2,734,095) (15,041) (2,749,136)Interest cost (130,171) (807) (130,978) (120,970) (677) (121,647)Current service cost (167,992) (2,652) (170,644) (161,902) (2,140) (164,042)Net benefit expense (recognized in P&L) (298,163) (3,459) (301,622) (282,872) (2,817) (285,689)Benefitspaid 132,224 - 132,224 75,927 - 75,927Experience different than assumed 241,263 182 241,445 (23,558) (83) (23,641)Changes in assumptions (98,689) 1,524 (97,165) - - -Sub total included in OCI 142,574 1,706 144,280 (23,558) (83) (23,641)Defined benefit obligation as at December 31(2,987,963)(19,694)(3,007,657)(2,964,598)(17,941)(2,982,539)95'