Private and social discount rates were estimated separately via Stata11 software.



Stata11
We searched PubMed, EMBASE and Proquest databases in June 2013. 
PubMed
We searched PubMed, EMBASE and Proquest databases in June 2013. 
EMBASE
We searched PubMed, EMBASE and Proquest databases in June 2013. 
Proquest