Further, a lack of comprehensive demographic data prevents us from concluding whether the solar initiative and the decal program have served a diverse population of Californians. However, the limited demographic data that does exist shows that participants in the solar initiative's General Market Program tend to be largely older, wealthier, and have received more education than most California homeowners. . . With respect to the decal program's capacity to appeal to a diverse population, a recent consumer survey for a related incentive program for low-emission vehicles found that, although the ages of respondents are somewhat evenly distributed, most respondents were male and earned $100,000 or more per year.