Eligible_surgery.txt 
#CaseHospital stay identifier
#HospitalHospital identifier
#SiteLocation of the hospital
YearYear (most recent year in the SQLape_input.txt file with at least 10% of records)
DS1Observed rate (= 1 if candidate for one-day surgery, 0 if not)
DS0Expected rate = 10% of eligible stay with surgery
RDSDay surgery ratio (DS1/DS0)
RDSminLower bound of the 95 confidence interval for RDS
RDSmaxUpper bound of the 95 confidence interval for RDS