The statistics in each link below reflect the number of babies which were prevented from getting spina bifida or anencephaly because of an active fortification program involving folic acid added to wheat and/or maize flour. As of 2019, the rate of prevention is estimated to be only 23% of the number which could be prevented with a global mandate to fortify staple foods with folic acid in 56 countries.
These data were generated and published by the Center for Spina Bifida Prevention.
Reference: A 2019 global update on folic acid-preventable spina bifida and anencephaly 
Fortification Regions