Military spending / GDP / Population

The EU and USA's military spendings combined make up more than 50% of the total global military budget. Also, if we look at the military budget/population ratio, we can see that the West is still far ahead the rest of the world, including China and Russia. 

But in the unstable geopolitical climate that we're all aware of it still doesn't seem enough. What's your opinion? Should Europe spend more on its defense? Is there any other way of keeping us and our region safe than through military force?