: A recent analysis of the profiles of more than 150 Americans convicted of espionage against the United States has revealed some interesting patterns.

Gender: 93 percent were men, 7 percent women.

Age: They were young, with 40 percent age 20-29, 27 percent 30-39, and another 27 percent 40-49. However, while 44 percent of civilians convicted of espionage were over 40 when they began their nefarious work, 57-percent of those in the armed forces got their start during their 20s.

Race: Most (84 percent) were white, 6 percent black, 5 percent Hispanic (who can be of any race), and 5 percent other. The others, which include East Asians, are over represented. This is because of high espionage activity by China. 

Sexual Orientation: 95 percent were heterosexuals, 5 percent homosexuals. There were few cases of homosexuals being blackmailed into spying.

Citizenship: 83 percent were natural-born citizens, 17 percent naturalized citizens. The naturalized citizens were over represented, which reflects that fact that many of them have close kin back in the old country.

Motivations: No percentages could be given, due to multiple causes, but the principal reasons cited were greed, sometimes prompted by financial problems, ideology, loyalty to a foreign country, spite (e.g., getting even with a superior), and serious personal problems, such as broken marriages.

The curious difference between the age at which military and civilian personnel begin spying appears to be due to a combination of the fact that people in the armed forces usually have access to classified information at a younger age than civilians working in the defense establishment or the defense industry, and the stresses of military life, including the financial traps that often snag young service members.

While the number of convicted spies may seem high, and naturally does not tell much about the number of people out there who have never been apprehended, its worth noting that something like 2.5 million Americans possess security clearances, and thus are likely to have access to sensitive information, a figure that is easily dwarfed by the number of people who lack clearances but nevertheless work in the defense industry and government, and sometimes have surprising access to valuable information.