Washington: The number of Americans living in poverty grew to 49.1 million, or 16 percent of the total population, under a new US Census Bureau methodology that gave more weight to day-to-day expenses.

Officially, some 46.6 million people in the United States, or 15.2 percent, live under the poverty line, but that figure is rooted in statistical methods dating back to the 1950s and based on pre-tax income.

The revised "supplemental poverty measure" for 2010 -- unveiled by the Census Bureau -- gives more weight to expenses such as taxes, work-related expenses, child care, child support and out-of-pocket medical expenses.

It also brings housing subsidies, food stamps, school lunches and programs to help pay energy bills into the mix.

Using the new formula brought down the rate of poverty among blacks, renters, those living outside big cities, those living in the Midwest and South, and those covered only by public health insurance.

On the other hand, the proportion of over-65s in poverty grew to 12.7 percent under the supplemental poverty measure, compared with 7.6 percent according to the official methodology.

The total number of those of Asian origin living in poverty rose to 2.4 million, compared to 1.7 million under the official measure.