San Rafael, Calif. ? Women living in wealthy Marin County, set in the wooded hills just north of San Francisco, suffer one of the nation’s highest breast cancer rates, a cluster that has confounded health officials.

On Saturday, about 2,000 volunteers went door-to-door through the county asking questions that could help point to an answer: How many residents have cancer, where do they live and do they have any idea why rates have climbed so high.

“My hope now is that everybody realizes that as a community we can change our statistics,” said Judi Shils, founder of the Marin County Cancer Project.

According to the Berkeley-based Northern California Cancer Center, white women living in Marin County are 45 percent more likely to develop breast cancer than women elsewhere in the country. A study the center released in July found cancer rates in Marin increased 37 percent during the 1990s ” even as they remained flat in the rest of the San Francisco Bay area and California’s other urban counties.

The researchers focused on white, non-Hispanic women because fewer than 10 cases of breast cancer are found each year in Hispanics, blacks or other populations in Marin County, which is 80 percent white.

Saturday, volunteers asked women residents a series of questions, ranging from age to family cancer history and whether they could identify any factors that might contribute to the cancer rate.

While Marin County residents and researchers alike continue to search for an environmental cause, some scientists say socio-economic factors could be involved in the high rate.

Marin County boasts a per capital income more than 200 percent the U.S. average, and 44 percent of its adults hold at least a bachelor’s degree. Some researchers believe lifestyles common in those populations ” bearing fewer children, having them later in life or taking estrogen and other hormones ” may trigger cancer.

Shils said the volunteers hoped to talk with 100,000 people and collect donations to fund an epidemiology map of cancer incidences based on 20 years of statistics gathered by the cancer center.