http://www.sph.emory.edu/wheatflour/index.php

The number of countries with mandatory wheat flour fortification has increased from 33 to 60 since 2004, and the map shows where other countries are in the planning stage.  The benefit:cost ratio for flour fortification has been used as one of the arguments to support advocacy for increased flour fortification.  (Note that similar benefits can be seen for fortification with folic acid to reduce neural tube defects, see for example Sayed, A-R, D. Bourne, R. Pattinson, J. Nixon and B. Henderson.  Decline in the prevalence of neural tube defects following folic acid fortification and its cost-benefit in South Africa.  Birth Defects Research (Part A) 82:211-216, 2008.