The average monthly number of employees (including executive directors) was:
| 2018
Number | 2017
Number |
| ADE: | | |
| Western Europe | 921 | 892 |
| North America | 851 | 827 |
| Emerging markets | 21 | 16 |
| AGI: | | |
| Western Europe | 2,021 | 1,945 |
| North America | 971 | 962 |
| Emerging markets | 748 | 688 |
| Shared services | 225 | 235 |
| Head office | 36 | 29 |
| 5,794 | 5,594 |
| 2018
£m | 2017
£m |
| Their aggregate remuneration comprised: | | |
| Wages and salaries | 247.6 | 242.5 |
| Social security costs | 34.6 | 33.1 |
| Other pension costs | 8.9 | 8.2 |
| 291.1 | 283.8 |
Included in wages and salaries are share-based payments resulting in a charge of £3.8m (2017: £7.8m).
Included in other pension costs are £7.0m relating to defined contribution schemes (2017: £6.7m), £1.9m relating to defined benefit schemes (2017: £1.5m) and £0.7m (2017: nil) relating to a one-off GMP equalisation charge as a result of the High Court ruling on 26 October 2018 in the landmark Lloyds Banking Group case on Guaranteed Minimum Pensions (GMPs).
Disclosure of individual directors' remuneration, share interests, share options, long term incentive schemes, pension contributions and pension entitlements required by the Companies Act 2006 and those specified for audit by the Listing Rules of the Financial Conduct Authority are shown in the tables in the Board report on remuneration and form part of these financial statements.