Refer to the table below relating to the Republic of Varlia.
| Year | Unemployment rate (% of active labor force) |
|---|---|
| 2019 | 4.1 |
| 2020 | 7.2 |
| 2021 | 8.5 |
| 2022 | 6.8 |
| 2023 | 5.0 |
| 2024 | 4.3 |
Which one of the following types of unemployment best explains the change in the Varlian unemployment data between 2019 and 2021?
Structural
Frictional
Cyclical
Seasonal