decode variants of country=US to 3-character code USA; otherwise, NULL (relies on high frequency of country=US, which is reasonable in our dataset)
decode variants of country=US to 3-character code USA; otherwise, NULL (relies on high frequency of country=US, which is reasonable in our dataset)

HSSC/scsqc,higgsmass/scsqc,HSSC/scsqc,higgsmass/scsqc