World Bank's threshold for poverty is $1.25 per person per day.
For a family of four this gives:
Daily income = (number of people) * threshold
Daily income = 4 * $1.25
Daily income = $5
For a year this is:
Yearly income = (daily income) *365
Yearly income = $5 *365
Yearly income = $1825
U.S. poverty threshold is set at $29000. Portion of threshold can be calculated as:

The poverty threshold measured by World Bank is 6.29% of the U.S. poverty threshold.