Kaplan & Rauh (2013) report that over time, the group of US billionaires in the Forbes 400 1. have had an increase in the percent of members that have been first-generation founders in the wealth generating business. 2. have had a decrease in the percent of members that have been fhrst-generation founders in the wealth generating business. 3. have had no change in the percent of members that have been first-generation founders in the wealth generating business. 4. They do not show data about this