Some child support laws and formulas do not adequately reflect the extent to which the child support payor supports the children, and the expenses the payor incurs in caring for the children. Many jurisdictions have tried to develop child support formulas and models that take into account the extent to which parents share custody, and adjust child support amounts in shared parenting arrangements in relation to the division of parenting time. In the UK a "non-resident" parent caring for the children 174 nights a year would have to pay the other parent (4/7) 57% of the maintenance they would have paid if they had provided no care. Thus, a "non-resident" parent may be obligated to pay up to 17% (31%*4/7) of his or her income as child support.