Table:
|  | 2015 Grant | 2016 Grant | 2017 Grant | 2018 Grant | 2019 Grant |
| --- | --- | --- | --- | --- | --- |
| Grant date | 1st October | 1st October | 1st October | 1st October | 1st October |
| Exercise price | 2,797.0p | 4,477.3p | 5,496.7p | 7,240.0p | 7,835.0p |
| Number of employees | 1,038 | 1,040 | 1,229 | 1,294 | 1,318 |
| Shares under scheme | 34,449 | 22,173 | 22,411 | 16,687 | 16,820 |
| Vesting period | 3 years | 3 years | 3 years | 3 years | 3 years |
| Expected volatility | 21% | 21% | 21% | 19% | 21% |
| Risk free interest rate | 0.4% | 0.1% | 0.4% | 0.8% | 0.5% |
| Expected dividend yield | 2.5% | 2.5% | 2.3% | 2.0% | 1.8% |
| Fair value | 2,931.3p | 4,696.7p | 5,799.0p | 7,623.7p | 8,305.1p |
Paragraphs:
Employee Share Ownership Plan
UK employees are eligible to participate in the Employee Share Ownership Plan (ESOP). The aim of the ESOP is to encourage increased shareholding in the Company by all UK employees and so there are no performance conditions. Employees are invited to join the ESOP when an offer is made each year. Individuals save for 12 months during the accumulation period and subscribe for shares at the lower of the price at the beginning and the end of the accumulation period under HMRC rules. The Company provides a matching share for each share purchased by the individual.
Shares issued under the ESOP have been measured using the Present Economic Value (PEV) valuation methodology. The relevant disclosures in respect of the Employee Share Ownership Plans are set out below.
The accumulation period for the 2019 ESOP ends in September 2020, therefore some figures are projections.
Question:
In which grant year was the risk free interest rate the highest?
Answer: Because 0.8%>0.5%>0.4%>0.1%, the answer is: 2018.