The global economy is growing at about 3% a year. This is roughly equal to the average growth rate for the last 50 years. However, growth predictions are ticking slightly downwards, mainly due to concerns around trade. And there are still high levels of government and corporate debt arising from the financial crisis and subsequent period of low interest rates. Nowhere is this better illustrated than China, which is forecast to overtake the US as the world's largest economy as early as this year, on some measures.