Study the table below, which contains data on the recorded annual rate of coastal erosion (retreat) in metres per year (m/yr\text{m/yr}m/yr) at five monitoring stations along a high-energy coastline in 2022.
Calculate the mean annual rate of coastal erosion for these five stations. You must show your working.
| Monitoring Station | Annual rate of coastal erosion (m/yr\text{m/yr}m/yr) |
|---|---|
| Station A | 1.8 |
| Station B | 2.3 |
| Station C | 1.5 |
| Station D | 3.1 |
| Station E | 2.5 |