I do not know the answer to Alexandra's question; however, I suspect it is nearly as high, among Orthodox in America, if "mixed marriages" are included. A mixed marriage is a marriage between an Orthodox Christian and a Christian, who had been baptized with water, in the Name of the Holy Trinity, by a Christian clergyman, who is attached to a denomination which confesses the Holy Trinity.
I am going to refer you to possible resources to assist with your inquiry. Go to the website of the Greek Orthodox Archdiocese of America, goarch.org. There is a department of church and family services (I don't recall the exact name). I recall an article in the "Orthodox Observer," by the priest who is the director of this department, published a number of years ago. In it, he analyzed the national divorce rate and explained that it isn't as high as is commonly interpreted. He indicated that when the 50% rate was first publicised, probably -30- years ago, the analyst who promoted this rate, simply took the number of divorces for that year, which were half of the number of marriages for the same year, and used that number to determin the 50% rate. This is an erroneous method, because it assumed that half of those who were married that year were divorced, using divorce statistics, that in actuality, were from marriages from various prior years. Again, as I recall, he computed about a 30% real divorce rate, not that that is anything to be happy with. The Yearbook of the Holy Archdiocese is also published on this website. In a chart compiled by the department of Vital Statistics, the annual figures of the Marriages and divorces (through Spiritual Courts) are reported, dating back quite a few years.