2. OPERATING PROFIT		1997 US$m	1996 US$m
The following items have been charged in arriving at operating profit:
- Depreciation of tangible fixed assets		141.0	129.8
- Amortisation of goodwill		1.7	1.0
- Operating lease rentals		293.4	278.2
- Pension costs:
defined benefit schemes		6.1	6.3
defined contribution schemes		23.7	24.0
- Foreign exchange transaction losses/(gains)		0.5	(0.6)
The following item has been credited in arriving at operating profit:
- External rental income		14.8	14.0