SLIDESHOW: Philippine underground economy workers
On May 1, labor groups will once again take up the cudgels of workers in the formal economy. But these workers make up only a small group of the Philippine labor force.
A bigger group comprises informal, mostly unorganized workers such as pedicab drivers, maids, and vendors.
They make up nearly half of the total labor force.
Their economic activities account for 20% of the country's Gross Domestic Product (GDP), which means they make key contributions to economic growth.
Here's a closer look at the "drivers" of the Philippine underground economy.