Just wondering, how does youtube pay your video...

Is it a one-time payment per content (e.g you make content on Jan then youtube pay only on Jan for that video)

or

Will they paid every month for every single video you have based on your current view on a single video (e.g you view on Jan is 1K then youtube paid 1K viewing then next month you get extra 500 view then youtube paid 500 view) ?