In fact, the correlation of socioeconomic status scores between the fathers of U.S. couples was found to be between .39 and .7 in 1973. Among the top 100 or 200 wealthy families in the U.S., inheritance is the overwhelming source of wealth. Thus, while many individuals work hard and improve upon their inheritance, without their inheritance they would be salaried employees who would have to depend on their life-time earnings in order to accumulate enough capital to begin a business late in life. Now, if an economy is a competitive one, opportunities for extraordinary profits as in oil are essentially transitory, but if barriers to entry prevent, for a time, outside competitors from joining the industry and thereby diluting the bonanza, much larger fortunes may be acquired. Thus an important variable is the degree of monopoly in any given economy.
Lets take a closer look at the distribution of wealth.
In the past two decades, the trend toward increasing concentration of wealth has returned. There are several summary measures used to assess the degree of income and wealth inequality. But this method requires five or six numbers and is often difficult to compare across time. Perhaps the most common single measure is the Gini index, created by Corrado Gini in 1912. The Gini coefficient measures the degree to which the distribution of income deviates from perfect equality.