The United States has historically been considered the richest country in the world, but data is starting to show that the levels of wealth in the world are slowly equalizing to some degree. Of course, there is still an enormous gulf between the net worth of the average U.S. citizen and someone in a third world country, but the standards of living in many other areas of the world are starting to catch up to the U.S.

Net Worth
In 2011, Credit Suisse published a detailed report breaking down the wealth and financial statistics that covers most of the countries in the world. It shows that in terms of region, roughly 28% of the world's gross wealth resides in North America, 34% of it is found in Europe and about 22% of it is an the Asia-Pacific sector and 9% is in China alone. It broke down the average net worth per adult by country into the following categories by U.S. dollars.

Less than $5,000
Majority of Sub-Saharan Africa, Bangladesh, Cambodia, Laos, Nepal, Sri Lanka, Vietnam, Belarus, Moldova and Ukraine.

From $5,000 to $25,000
Majority of the countries in Latin America, a large portion of countries bordering the Mediterranean, China, India, Indonesia, Pakistan, Philippines and Russia.

From $25,000 to $100,000
Chile, Brazil, Mexico, Uruguay, Czech Republic, Estonia, Hungary, Lithuania, Malta, Poland, Slovenia, Bahrain, Lebanon, Oman, Saudi Arabia, Turkey, South Africa and Namibia.

From $100,000 to $300,000
North America, Western Europe, rich Asia-Pacific and Middle East countries.

From $300,000 to $500,000
Australia and Norway

Over $500,000

Cost of Living
Although this data isn't exactly surprising, it doesn't tell the entire story when comparing the net worth of people in different parts of the world. Obviously, the cost of living also varies substantially from one country and region to another, and the debt-to-income ratio of households in the top categories are now higher than ever. This is a factor that could eventually affect these rankings in the future. A survey published by Kiplinger's magazine in January 2012 broke down the cost of living along with several other financial and economic factors in several cities around the globe. It revealed that those who live in Tokyo work an average of nearly 50 hours a week and took home an average paycheck of $135,000 in 2011, which is understandable given that the price of an upscale two-bedroom apartment there is a whopping $5,044 per month in U.S. dollars.

Americans who complain about the price of gas may want to think carefully before leaving the country. The price of gas in Ankara, Turkey is just over $9.50 a gallon and is over $7.00 a gallon in Athens, Rome, Stockholm, London, Berlin and Tel Aviv. It is around $6.00 a gallon in Tokyo and Madrid and over $4.00 in Ottawa, New Delhi and Beijing.

Tokyo again leads the world in the average cost of groceries. If you use the cost of groceries in Washington D.C. as the mean, then Tokyo's groceries cost 35% more on average, with Ottawa and London only beating Washington D.C. out by a few percentage points each. Stockholm, Rome and Tel Aviv are close behind, while Berlin, Athens, Madrid and Beijing lag more substantially. New Delhi and Ankara boast the lowest costs in this sector.

The Bottom Line
Although the countries in the top categories of net worth per adult still boast the highest standard of living, many of them also come with the highest costs of living as well. Time will tell how these factors change with the continuing development of the lower-tier countries in the world.