rack sth up
phrasal verb with rack verb [ T ] uk/ræk/ us
to gradually gain a large amount of something:
The government and debt counsellors believe it is too easy to rack up large numbers of loans.
The company's dozen vehicles rack up 144,000 miles a year.
He'll rack up $10,000 in bonus money.
rack sth up into sth Try to rack these small returns up into modest but consistently positive returns.