How many? Also do you know the answer to the question you cut and pasted ... presumably you've read both those links so you know if there's a quantitative treatment?

All I could find about Haiti wrt the Sisters of Mercy was that the SoM went there in 1991 (according to graphic here, http://www.mercyworld.org/mercy_network/network-map.cfm). Whilst Susan Shields left the order in 1989 after 9 years "living in the Bronx, Rome, and San Francisco" and apparently then published her story of the situation in Haiti that so shocked her another 9 years later in 1998 (http://secularhumanism.org/library/fi/index_18.html, http://www.texnews.com/1998/religion/morph0117.html).

I don't have access to the text in the Lancet (which turns out to be a letter to the editor, and so not reviewed) - do you have a link to an open access version?

I realise we're way OT, but I'm keen to investigate this.