Complex sentence: The census of 1 April 2009 recorded the population of Vietnam as standing at approximately 85.8 million, of which the Viet or Kinh ethnic group constituted nearly 73.6 million, or 85.8% of the population.
Split into simpler sentences: The census of 1 April 2009 recorded the population of Vietnam as standing at approximately 85.8 million. According to the 2009 census, the dominant Viet or Kinh ethnic group constituted nearly 73.6 million people, or 85.8% of the population.