8.	Segmental analysis

Reported contributions by operating sector were as follows:


	Six months ended 30 June 2018			Six months ended 30 June 2017¹			Year ended 31 December 2017¹
	£m			£m			£m

Revenue
Advertising and Media Investment Management		3,441.1			3,570.1			7,368.7
Data Investment Management		1,236.0			1,313.5			2,703.4
Public Relations & Public Affairs		581.1			597.4			1,204.0
Brand Consulting, Health & Wellness and Specialist Communications		2,234.5			2,169.4			4,528.1
		7,492.7			7,650.4			15,804.2

Revenue less pass-through costs²
Advertising and Media Investment Management		2,639.0			2,848.2			5,889.3
Data Investment Management		946.0			996.7			2,052.1
Public Relations & Public Affairs		550.6			567.9			1,140.6
Brand Consulting, Health & Wellness and Specialist Communications		2,013.3			1,963.3			4,087.6

Headline PBIT³
Advertising and Media Investment Management		380.3			431.8			1,109.0
Data Investment Management		112.3			129.2			350.3
Public Relations & Public Affairs		85.2			79.7			183.2
Brand Consulting, Health & Wellness and Specialist Communications		242.9			241.3			624.6
		820.7			882.0			2,267.1

Headline PBIT margin⁴
Advertising and Media Investment Management		14.4	%		15.2	%		18.8	%
Data Investment Management		11.9	%		13.0	%		17.1	%
Public Relations & Public Affairs		15.5	%		14.0	%		16.1	%
Brand Consulting, Health & Wellness and Specialist Communications		12.1	%		12.3	%		15.3	%

Notes

¹	Prior year figures have been restated for the impact of the adoption of IFRS 15: Revenue from Contracts with Customers, as described in note 2.

Revenue less pass-through costs is revenue less media, data collection and other pass-through costs. Pass-through costs comprise fees paid to external suppliers where they are engaged to perform part or all of a specific project and are charged directly to clients, predominantly media and data collection costs. See note 5 for more details of the pass-through costs.

³	A reconciliation from profit before interest and taxation (PBIT) to headline PBIT is provided in note 21.

⁴	Headline PBIT margin is calculated as headline PBIT (defined above) as a percentage of revenue less pass-through costs. Previously referred to as revenue less pass-through costs margin.

Reported contributions by geographical area were as follows:


	Six months ended 30 June 2018		Six months ended 30 June 2017¹		Year ended 31 December 2017¹
	£m		£m		£m

Revenue
North America²		2,598.1		2,818.5		5,659.2
United Kingdom		1,091.5		1,047.5		2,133.4
Western Continental Europe		1,609.9		1,525.5		3,230.6
Asia Pacific, Latin America, Africa & Middle East and Central & Eastern Europe		2,193.2		2,258.9		4,781.0
		7,492.7		7,650.4		15,804.2

Revenue less pass-through costs³
North America²		2,155.2		2,407.2		4,793.9
United Kingdom		832.9		814.7		1,688.0
Western Continental Europe		1,319.2		1,236.5		2,630.6
Asia Pacific, Latin America, Africa & Middle East and Central & Eastern Europe		1,841.6		1,917.7		4,057.1

Headline PBIT⁴
North America²		348.1		400.9		937.4
United Kingdom		109.7		112.4		280.0
Western Continental Europe		136.3		153.1		376.0
Asia Pacific, Latin America, Africa & Middle East and Central & Eastern Europe		226.6		215.6		673.7
		820.7		882.0		2,267.1

Headline PBIT margin⁵		%		%		%
North America		16.2		16.7		19.6
United Kingdom		13.2		13.8		16.6
Western Continental Europe		10.3		12.4		14.3
Asia Pacific, Latin America, Africa & Middle East and Central & Eastern Europe		12.3		11.2		16.6

Notes

¹	Prior year figures have been restated for the impact of the adoption of IFRS 15: Revenue from Contracts with Customers, as described in note 2.

North America includes the US with revenue of £2,454.1 million (period ended 30 June 2017: £2,660.8 million; year ended 31 December 2017: £5,336.3 million), revenue less pass-through costs of £2,038.6 million (period ended 30 June 2017: £2,279.3 million; year ended 31 December 2017: £4,535.3 million) and headline PBIT of £328.9 million (period ended 30 June 2017: £382.2 million; year ended 31 December 2017: £937.4 million).

⁴	A reconciliation from profit before interest and taxation (PBIT) to headline PBIT is provided in note 21.

⁵	Headline PBIT margin is calculated as headline PBIT (defined above) as a percentage of revenue less pass-through costs. Previously referred to as revenue less pass-through costs margin.