UK US rack sth up
— Phrasal Verb with rack({{}}/ræk/ verb [T]
► 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.
Financial and business terms. 2012.