| 2018 | 2019 | 2020 | 2021 (forecast) | |
|---|---|---|---|---|
| Country A production of coal (thousand tonnes) | 360 000 | 320 000 | 250 000 | 175 000 |
| Index of Country A production of coal | 144 | 128 | 100 | ? |
| Country A imports of coal (thousand tonnes) | 120 000 | 150 000 | 200 000 | 240 000 |
| Index of Country A imports of coal | 60 | 75 | 100 | 120 |
Note: Indices are based on 2020 = 100.
Using Extract A, calculate the index of Country A's production of coal for 2021
identify one significant feature of the data for the years 2018 to 2020 .
