I’ve selected 3 variables (IND, OCC, STATEFIPS) and 1 sample (5% 2000). I am interested in selecting cases along the IND variable, so that the data will only reflect persons who work in pharma and medicine manufacturing (181, or NAICS 3254)However when I click on “Select Cases” to choose cases fitting this criterion, IND does not come up as an option. Only STATEFIPS and Group Quarters. Should I be doing something differently?