It's hard to distinguish correlation from causation. If a country imports more IP than it exports, then enforcing IP laws quite clearly bleeds money from it. If citizens spend money on local non-IP industries instead of foreign IPs, the country has more money. But if the local IP industry is strong enough, it can bring money from other countries, and local IP enforcement can help support the industry that brings potential foreign money inflow. That is, assuming IP "enforcement" increases money spent on IP, which isn't always the case.