A dog may be man's best friend, but a credit card may be a woman's best friend. While the nation's male population is growing at a slightly faster rate than the female population, nearly 76.1 million women have or use credit cards, compared with 68.2 million men. VISA ranked as the #1 card with a total of 49.9 million female consumers or 66%. VISA's overall market share among all cardholders is about 52% in the USA. American Express was less favored by women than the Sears Card (22.5 million), the J.C. Penney Card (20.6 million), and the Discover Card (17.9 million). This comes as no surprise to many credit card issuers. The industry has long known that women tend to respond to lower interest rates offers while men favor reward programs. The findings come from a MarketResearch.com/Simmons Market Research Bureau co-branded study released this week. The latest Census 2000 data shows the male and female populations were 138.1 million and 143.4 million, respectively. The difference between the female and male populations dropped from 6.2 million in 1990 to 5.3 million in 2000. This resulted in a male-female ratio (the number who were male times 100 divided by the number who were female) that increased from 95.1 in 1990 to 96.3 in 2000.