Development of plan obligations

	Pensions plans		Other long-term benefits
in CHF thousands	2017	2016	2017	2016
As at 1 January	516'504	483'502	3'914	4'092
Current service cost	17'911	16'090	449	452
Plan participation contributions	7'166	6'910	0	0
Interest costs	3'565	3'981	27	33
Benefits paid through pension assets	−13'980	−6'026	0	0
Benefits paid by employer	−12	−2	−624	−536
Actuarial (gains) / losses	1'768	22'251	20	−125
Plan amendments	1'118	−10'202	0	0
Exchange rate differences	5	0	25	−2
As at 31 December	534'045	516'504	3'811	3'914
of which active employees	372'297	357'399
of which pensioners	161'748	159'105

Average term of obligation	17.7	18.3