Fewer Marrying Foreigners

There has been a rather steep decline in the number of Chinese-foreign marriages in China in recent years. The number of Chinese marrying foreigners reached its peak at the turn of the century. There were 79,000 Chinese-foreign marriages in 2001. 53,000 such couples tied the knot in 2012. You would assume with China opening up to the world, more international marriages will take place. Why is there a decline?