I need info. on child support payments in Nor.-America & Europe when both parents have same and average income

in my state, if one parent has custody and the other does not, the child support payments vary by the income of the paying party, without regard to the income of the custodial parent. The court will follow a formula devised by the legislature, so that support for one child amounts to 18 percent of the gross income of the non-custodial parent, and two kids is 25 percent and three kids is 29 percent. The legislature has also provided caps. Then, in addition, the court will fix responsibility for medical care or insurance and can make adjustments for special cirstances such as for kids with special needs.