If you start from the original poverty definition of $1/day (1985 dollars) that was used in writing up MDG-1 and then correct for inflation in the US in the 1985-2005 period, you arrive at an equivalent poverty line of $1.815/day (2005 dollars), much higher than what you indicate (www.bls.gov/data/inflation_calculator.htm).
You can go to PovCalNet (http://iresearch.worldbank.org/PovcalNet/index.htm) to see what a difference this makes. If the poverty line is fixed where the World Bank now fixes it, at $1.25/day (2005)
= $38/month (2005), then the number of poor is 1908.45m in 1990 and 1214.98m in 2010 for a 36.34% reduction over twenty years -- enough to halve the proportion
of poor in the LDC population.
If the poverty line were fixed at the inflation-adjusted equivalent of where it was initially fixed, at $1.815/day
(2005) = $55.18/month (2005), then the number of poor is
2698.42m in 1990 and 2146.68m in 2010 for a mere 20.45% reduction over twenty years -- nowhere near enough to halve the proportion of poor in the LDC population.
All the best,
Professor of Philosophy and International
Yale University, PO Box
208306, New Haven, CT