The US-China power balance
Talks between US President Barack Obama and Chinese President Hu Jintao are being billed as the most important meeting between the two countries for 30 years. It comes at a time when relations have been strained by issues such as the trade imbalance and China's growing military might.
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- The US buys far more than it sells to China - the US claims this is because China has kept its currency artificially weak. In fact trade with China accounts for 14.3% of all US trade - the States only does more trade with Canada.
- Until the 1990s, the US economy grew strongly while China remained relatively stagnant. Since 2000 China's growth rate has surged, driven by economic reforms, a huge workforce and massive investment.
- The US defence budget is the biggest in the world at around $700bn. China has the second largest - but its official military budget has soared since 1999 as the country's economy has grown.
- China is the most populous country in the world ahead of India and the US. Its huge population has helped drive economic growth but it has also put huge stress on resources and air and water pollution are big problems.