Note, though, that the growth rate differential between the US and China is currently around 7 percent per year (e.g., 10 vs 3). If that persists for another decade, China's PPP GDP will exceed that of the US.
See here for a list of PPP adjusted GDPs by country.
70% of US GDP is consumer-related. One can expect significant consequences abroad from any slowdown here -- for example due to freezing of home equity lines of credit ;-)
