Import Wizard Issue

Hello. I've created a .csv file using the Import Wizard to import a .csv mailing list of 5,000 names and addresses with altnum name finder number for the csrs. When I run my Import job it only pulls in 150 customer names/addresses at a time. What am I doing wrong that it doesn't keep going and do the whole file. I have no dup checked off and the list doesnt have duplicates. Every time I run the mod it imports in 150 more names.

What is causing the 150 customer limit per import from same list?

Very frustrating.

Thanks!