pass1 - making usageList (24 chroms): 142 millis pass2 - checking and writing primary data (1001046 records, 3 fields): 898 millis pass1 - making usageList (24 chroms): 74 millis pass2 - checking and writing primary data (519333 records, 3 fields): 487 millis pass1 - making usageList (24 chroms): 33 millis pass2 - checking and writing primary data (230703 records, 3 fields): 225 millis pass1 - making usageList (24 chroms): 19 millis pass2 - checking and writing primary data (133664 records, 3 fields): 138 millis