Hosting the Olympics is a costly business – and the final price can escalate quickly – according to a new study.

A Summer Olympic Games now costs an average of $5.2bn (at 2015 levels), while the average Winter Olympics costs $3.1bn, a working paper from The University of Oxford and Said Business School found. And these figures only include sports-related costs.

Moreover, no Games since 1960 has come in under budget. In fact, nearly half have cost overruns of more than 100%. Montreal 1976 had a cost overrun of 720%, Barcelona 1992 of 266% and Lake Placid 1980 of 324%.