DHS has published Visa Waiver Program (VWP) overstay rates admitted into United States for business and pleasure.
The Visa Waiver Program (VWP) is a program of the United States Government which allows citizens of specific countries to travel to the United States for tourism, business, or while in transit for up to 90 days without having to obtain a visa. The program applies to the United States as well as the US territories of Puerto Rico and the US Virgin Islands in the Caribbean, with limited application to other US territories.
Citizens of 38 countries and territories are eligible for visa-free entry into the United States under the VWP
For VWP countries, the FY 2017 Suspected In-Country Overstay rate is 0.51 percent of the 22,472,710 expected departures.
Portugal, Hungary and Spain have the highest overstay rates under the VWP
To qualify for the Visa Waiver Program, a country must have had a nonimmigrant visa refusal rate of less than 3% for the previous year or an average of no more than 2% over the past two fiscal years with neither year going above 2.5%
According to CBP website
If you entered the United States on the Visa Waiver Program and stayed longer than the admission period granted by CBP at your time of arrival, you are no longer eligible for the Visa Waiver Program. You will require a non-immigrant visa for entry in the future. You can find visa information at www.state.gov.
If you entered the United States on a non-immigrant visa, such as a tourist visa (B1/B2), and stayed longer than the admission period granted by CBP at your time of arrival, your visa is no longer valid pursuant to Section 222(g) of the Immigration and Nationality Act (INA).