Study Table 1, which shows the projected assets at risk from coastal erosion along the Holderness Coastline in East Yorkshire by 2080.
| Asset type | Quantity at risk from coastal erosion |
|---|---|
| Residential properties (number) | 5,400 |
| Holiday park caravan pitches (number) | 1,850 |
| B-roads (kilometres) | 46 |
| Secondary local roads (kilometres) | 131 |
| Coastal public footpaths (kilometres) | 85 |
| Community and heritage sites (number) | 18 |
| Grade II agricultural land (hectares) | 3,150 |
Calculate the mean length (in kilometres) of the transport and pedestrian routes (B-roads, secondary local roads, and coastal public footpaths) at risk from coastal erosion.
Give your answer to the nearest whole number.
You must show your working.