An estimated 7.6 million Americans will be regularly working as providers in the on-demand economy by 2020, more than doubling the current total of 3.2 million, according to a new study and forecast from Intuit Inc. (NSDQ:INTU) and Emergent Research. The on-demand labor market will grow by 18.5% a year over the next five years, according to the report.

The study also found 79% of existing on-demand providers said their on-demand activity is part-time.

“The rapid growth of on-demand marketplaces is reducing the traditional friction of finding customers, enabling a new class of entrepreneurs to find a hungry market for their products and services,” said Alex Chriss, VP and general manager of self-employed solutions at Intuit.

The current number of people working in the on-demand economy — 3.2 million — is based on an online survey of 2,276 US adult residents conducted between July 27 and Aug. 5.

The forecasted growth to 7.6 million by 2020 was derived by using a combination of analysis of historical data on the on-demand economy and the use of a diffusion of innovation (S curve) model

Intuit and Emergent Research are preparing a study that provides a detailed analysis of the demographics, motivations and challenges of workers pursuing on-demand jobs. The study will roll out over the coming months.

“The on-demand economy is poised to transform long-held assumptions about how the labor market works,” said Steve King, partner at Emergent Research. “It’s vital that we hear directly from the workers who are on the front lines of this shift so that we have the objective data and analysis we need to make informed policy choices.”