How Many Orthodox Christians are There in North America and the World?

Can you tell me how many Orthodox Christians there are in North America and throughout the world?
While it is somewhat difficult to give an exact figure—in North America there are a variety of numbers which circulate while on the world scene it is also difficult since many Orthodox churches, especially those in the former Soviet-bloc countries, are only now in a position to ascertain a clear picture of their status—I am happy to offer the following information.
North America:

One will find estimates ranging between 1 and 6 million members.

There is a certain variable in how one defines “membership”—for example, is membership based on the number of individuals baptized in the Orthodox Church, some of whom may no longer be Orthodox, or on other criteria such as financial support, registration with a local parish, etc?
It would be safe to say that there are somewhere between 2 and 3 million Orthodox Christians in North America in roughly 2,000 parishes. 

While some media report upwards of 300 million Orthodox throughout the world, others estimate 200 million. To give you an idea, it is estimated that there are somewhere between 80 and 100 million Orthodox in the Russian Republic alone. Since the fall of communism the churches in Central and Eastern Europe are in a period of transition, a part of which is coming to grips with actual membership statistics, which were impossible to maintain during the communist era. Another difficulty in estimating the international numbers is found in the mobility of many individuals from traditionally Orthodox areas, such as the former Yugoslavia, the Middle East, etc.

In my own opinion, the 200 million number is probably more accurate than 300 million, but this again depends on how one defines “member”—as a baptized individual, a registered individual, or a practicing individual who regularly participates in the life of the Church, her sacraments and worship, etc.
Source: https://oca.org/questions/namerica/how-many-orthodox