One of the few pieces of academic research examining the question of rates or turnover at international schools was conducted my Mancusso (2010) who looked just at member schools of NESA (Middle East and Sub-Continent). His research found that those schools reported an average of 17% annual teacher turnover. Interestingly this matches the rate of turnover found in the US by the best research available (Ingersoll, 2008).

My current school, a large American School in the UAE has averaged 20% over the past three years.

This school has ended a teacher contract (mid year) because of their sexual preference.
They have very few experienced international teachers, and those few that they do hire often leave before completing their contract. Teacher turnover rates have been in excess of 35% for their first two years of operations with many teachers leaving mid-year.
The students generally have very low English levels (despite its name, this is not an international school. All students are Chinese.)

Shenyang can be a difficult place to live. It does have freezing daytime temperatures for 5 or 6 months a year. It has few expats and entertainment options. Worse yet, the school is located around an hour from the city center.

I list these fact just to put perspective on this school. Having said that, the students work hard and are generally good-natured. The staff is under experienced, but they are all good people.