$ million	H1 2019	H1 2018	Change	Constant currency change
Revenue	1,047	979	7%	8%
Core revenue	1,043	979	7%	7%
Gross profit	548	490	12%	12%
Core gross profit	544	495	10%	11%
Operating profit	238	174	37%	37%
Core operating profit	246	214	15%	15%
EBITDA	297	230	29%	30%
Core EBITDA	288	252	14%	14%
Profit attributable to shareholders	185	106	75%	75%
Core profit attributable to shareholders	176	148	19%	20%
Basic earnings per share (cents)	76.4	44.0	74%	75%
Core basic earnings per share (cents)	72.7	61.4	18%	19%
Dividend per share (cents)	14.0	12.0	17%	-
Net cash flow from operating activities	187	185	1%	-