Unfortunately such a statistic does not exist and even if it did exist, it would probably not be accurate. As you know, the world is a very complex place, especially when it comes to the economy. However, we are not at a complete loss. There are some key points that we can examine.
First, foreign investments certainly help an economy. Just think of China. They are now a super power, partially, because the world choose to invest in China. So much of manufacturing went there and this created jobs, infrastructure, and so much more. Hence, with confidence we can say that foreign investments help local economies.
Second, there are many places where there is still great poverty. This means that foreign aid is still not making a big difference. In part, foreign aid is not sustainable. Moreover, wealthy countries cannot invest in all countries.
In light of these points, foreign aid and investment is not solving the problem of global poverty. Individual nations can be helped, but to help the world there needs to be something else.