Infant mortality

Nicholas Kristof writes:

If it's shameful that we have bloated corpses on New Orleans streets, it's even more disgraceful that the infant mortality rate in America's capital is twice as high as in China's capital. That's right - the number of babies who died before their first birthdays amounted to 11.5 per thousand live births in 2002 in Washington, compared with 4.6 in Beijing.

While I share Kristof's outrage at the Bush Administration's disgraceful response to the disaster in New Orleans and his concern about the poor in America, I wonder about this figure. I suspect that when health authorities in Beijing calculate infant mortality rates, they are looking at infants born to registered residents of Beijing. I believe there are something like 3 million migrant workers in Beijing whose childern are not counted. Since these workers basically have no access to health care, the real infant mortality rate is likely to be much higher.