expression for control

[nonrev1]

My report is already producing a column [Lvl] that is displaying level 1, 2, and 3 accounts. I made it count all of them but what expression can I use to specify a count of only level 1 accounts? I've tried a hundred different ways

 

[Pat Hartman]

=Sum(IIf(Lvl = 1, 1,0))