[Cincinatus' Wife]

Wages for laborers can be as much as five times higher than in the rest of the country - where the urban minimum wage is $4 a day - and the people of Monterrey study an average of three years more than other Mexicans. The crime rate is among the lowest for Mexico's metropolitan areas, and its police are considered among the least corrupt.

Now that sentence wasn't very clear.
Is it saying that the minimun wage in Monterrey is $4 a day or that is what it is in other urban areas?
I read it to mean it is $20 a day in Monterrey.

[Willie Green]

I read it to mean it is $20 a day in Monterrey.

For a 9 hour workday, that would still work out to $2.22 per hour.
Nobody's going to pull themselves up by their own bootstraps on that wage.