What are the key factors driving the rise of venture capital in the 1980's?

As a response to comments questions, I'd like to ask this: When the tax code changed in 1978 (Capital Gains Tax Reduction Act) and went from 40% to 25% why did Venture Capital skyrocket in the 1980's? Additionally, the 1981 ECBP tax act allowed for the creation of ESOPs and the 1986 tax act didn't change the capital gains tax rate. So, what were the main factors that pushed venture capital to grow in the 1980s?