The U.S. needs more IPOs in order to maintain a healthy venture capital industry, according to a new report from Deloitte & Touche.

The 2011 Global Venture Capital Survey from Deloitte and the National Venture Capital Association checked in with venture capitalists from around the globe, 80 percent of whom said current IPO activity levels are too low. Despite the number of companies who have recently gone public (Pandora and LinkedIn) or have filed for an IPO (Groupon, Zillow and PopCap Games), 87 percent of venture capitalists in the U.S. say the country needs to see more IPOs, which they deem critical to the venture capital industry.

Most venture capitalists said the high returns gained from IPOs encourage further investment and allow them to provide growth capital to younger companies.

"The venture-backed IPO market has been an extraordinary creator of economic value in countless ways," said Mark Heesen, president of the National Venture Capital Association, in the report. "Not only have millions of jobs been created, but superior returns have been delivered to pension beneficiaries, endowments and charitable foundations for decades. Entire industries have been formed, pushing innovation forward, and changing the way we live and work for the better. The recovery of the IPO market, both here in the U.S. and abroad, is not a nicety but a necessity for the future health of the global economy."

The slowdown in IPO activity can be attributed to certain factors that are necessary to a vibrant system. Venture capitalists say the market needs stronger investor appetite for equity in public companies, a stable economic environment, more adequate stock analyst coverage, a competitive investment banking community, and easier reporting for newly public companies.

"Clearly the industry continues to feel the ripple effects of the global economic downturn -- most notably in the form of limited exit opportunities," said Mark Jensen, a partner at Deloitte and national managing partner for venture capital services in a statement. Jensen said that the tide may be turning, due to an improving economy and the easing of the liquidity crisis, but that innovation is an important driver to economic health.

"And a strong exit marketplace is critical to the venture capital ecosystem driving much of that innovation," said Jensen.

Despite the challenges, there are some signs of improvement. Of VCs investing outside their home countries, more than half plan to increase investment activity over the next five years and 35 percent plan to maintain their current level of investment.

The survey found that current investor excitement is centered around IT -- especially cloud computing -- clean tech, social media and healthcare.