Quarterly youth unemployment rate in Nigeria 2018-2020

The source adds the following information: "[...] all countries however use the International Labour Organization's (ILO) definition, or a variant of it to compute unemployment. The ILO definition covers persons aged 15–64 who during the reference period (which is usually the week preceding the time the survey is administered) were available for work, actively seeking work, but were unable to find work.
The Nigerian National Bureau of Statistics, like most countries in the world, uses a variant of the ILO definition such that the unemployment is the proportion of those in the labour force (not in the entire economic active population, nor the entire Nigerian population) who were actively looking for work but could not find work for at least 20 hours during the reference period to the total currently active (labour force) population. Accordingly, you are unemployed if you did absolutely nothing at all or did something but for less than 20 hours during the reference week.
Hence, the unemployment rate is calculated as a percentage of the number of unemployed persons in the labour force:
Unemployment Rate=100 × (Unemployed Population)/(Labor Force Population)"

Figures taken from several publications.