The frequency of capital calls is generally determined by the needs of the fund (for deployment, fund expenses, etc.) and the discretion of the management. Most funds call 20% or 25% of committed capital upon the first close, after which it normally takes 12 to 18 months to close the remainder of the fund. During this period, funds typically do not call additional capital. When the fund is fully closed but within the active investment period, managers generally make capital calls as needed. 

Capital calls are not normally done per deal or on a set percentage each month or quarter.