Per Placement Costs USA, Shenzhen, Mexico

[radiostuff]

I do production runs of about 1000 boards in Shenzhen. From small assembly houses, the market price per placement is about a half-cent (USD). The low-end of US-assembly, which I priced 12-months ago, was 10-cents per placement. Does anyone know how anything about Mexican assembly houses and their per-placement prices? Are they usually located in a particularly part of the country?