Please answer a question about the following article about 2008 Sichuan earthquake:

Reginald DesRoches, a professor of civil and environmental engineering at Georgia Tech, pointed out that the massive damage of properties and houses in the earthquake area was because China did not create an adequate seismic design code until after the devastating 1976 Tangshan earthquake. DesRoches said: "If the buildings were older and built prior to that 1976 earthquake, chances are they weren't built for adequate earthquake forces."

When did China create a seismic design code for building?
1976