I believe GP means “open” in the sense of having a high degree of trade with the rest of the world. The US economy has more of a closed loop in that it consume

I believe GP means “open” in the sense of having a high degree of trade with the rest of the world. The US economy has more of a closed loop in that it consumes much of what it produces. China on the other hand imports most essential commodities and pays for them with the proceeds of exports.