What is the gross monthly of an E-7 in the Marine Corps with 12 years of service and dependents?

I don't want to come across as a "gold digger" but my ex has been fighting an increase in his child support for almost a year now. From prior experience in the Marine Corps I know for a fact that an E-7 makes way more than $3300 a month. The problem I am having is that he keeps lying about his wages. Can anyone help me find proof that an E-7 makes more than $3300 a month? I don't want any more child support than I am entitled to, but it seems to be slightly unjust that he can lie and get away with it, meanwhile I tell the truth and get penalized for it.