How often are expense ratios charged?

I noticed the expense ratio of the iShares EEM (Emerging Markets) ETF is .72%. How often am I charged this expense? And does it mean I am charged .72% every time I buy or sell a share?

 

Expenses come out of the distributions that get paid out.

 

I'm a little confused..... Perhaps we are thinking the same thing but this will add more detail:

Expense ratios accrue DAILY in the fund and are allocated to a sub-account until paid out. This way, each shareholder pays their fair share of the expense ratio on the date they hold the fund. Think of it as a tiny amount of money being chipped away from your NAV price each night.

 

.72% is an annualized figure. As already mention you are not charged this amount directly so to answer your second question - no.