| Supplier | Active Accounts (millions) |
|---|---|
| British Gas | 7.5 |
| E.ON Next | 5.0 |
| OVO Energy | 4.5 |
| Octopus Energy | 4.0 |
| EDF Energy | 3.0 |
| Scottish Power | 2.5 |
| Independent/Others | 3.5 |
| Total | 30.0 |
Calculate the four-firm concentration ratio from the table above. You are advised to show your working.
