

3.	EMPLOYEES

The average number of persons, including Executive Directors, employed by the Company is as follows:



	Years ended December 31,
	2014	2013	2012
Total average number of employees for the year	18,200	17,900	17,500

Salaries and benefits expense comprises the following:



	Years ended December 31,
	2014			2013			2012
	(millions)
Salaries and other compensation awards including amortization and write-off of cash retention awards of $10 million, $6 million and $416 million	$	2,069		$	1,953		$	2,258
Share-based compensation	52			42			32
Severance costs	8			32			6
Social security costs	147			135			133
Retirement benefits — defined benefit plan (income) expense	(17		)	(4		)	2
Retirement benefits — defined contribution plan expense	55			49			44
Total salaries and benefits expense	$	2,314		$	2,207		$	2,475

Severance Costs

Severance costs that have arisen in the normal course of business amounted to $8 million in the year ended December 31, 2014 (2013: $4 million; 2012: $6 million).

During the year ended December 31, 2013, the Company incurred additional salaries and benefits costs of $29 million of which $28 million related to severance costs, in relation to an Expense Reduction Initiative in the first quarter. These costs related to 207 positions that were eliminated.