For 17 days each year, Spoleto Festival USA and its local counterpart, Piccolo Spoleto, add exponentially to Charleston's charm and become the Lowcountry's dominant economic driver.

The final numbers for this year's Spoleto Festival will not be tabulated until after the Sunday finale. But as of June 1, the 11th day of the festival, sales were edging toward 60,000 tickets for its more than 120 performances, according to Jennifer Scott, the festival's director of marketing and public relations. The total number of tickets sold over all 17 days last year was 63,000.

Piccolo Spoleto runs the same length, with more than 500 events showcasing local and regional artists. These events complement Spoleto programming and are staged all over town - in theaters, parks, churches, galleries and other venues.

"Part of our model for success, and why the festival is still going strong 36 years on, is that we provide a platform for local art and artists to participate," said Scott Watson, director of the city's Office of Cultural Affairs.

While Spoleto is a nonprofit operating on a budget of $6.85 million this year, Piccolo is organized by the city's cultural affairs office and spends about $750,000 on the festival (not including overhead), Watson said. Many of the events are presented by others who apply to participate in the festival, but the city does produce some of the offerings, such as the Spotlight Concert Series, and it manages the box office, garnering 20 percent of ticket sales. The goal, Watson said, is for the city to break even and for artists to benefit financially.

Julia Forster, director of development at Spoleto, described the festival's budget as "slightly higher for this year compared to 2013, probably by $170,000 more, but that's mostly due to the increase of projected ticket sale holds."

Most income is generated by ticket sales and private donations. The festival relies increasingly on individual donors who provide about 55 percent of the total operating budget, Forster said in a recent radio interview.

Spoleto charged between $15 and $150 for tickets this year; Piccolo ticket prices ranged from $11 to $55, not counting its many free events.

Jennifer Scott said the profitability of any specific show depends on a number of factors, including the ticket prices and that show's expenses. She listed the English pianist Gwilym Simcock and the American premieres of "A Simple Space" and "A Brimful of Asha" as audience favorites so far.

It bears mentioning that these three shows were in the festival's two smallest venues, the Simons Center Recital Hall (260 seats) and the Emmett Robinson Theatre (318 seats).

The single largest audience thus far has been a concert by banjo artists Bela Fleck and Abigail Washburn that brought 2,200 people to TD Arena, and the chamber music series has been a consistent hit at the 463-seat Dock Street Theatre.

This year also featured three operas, "Facing Goya," "Kat'a Kabanova" and "El Nino," with the latter two in particular featuring large casts and orchestras. The festival faced some pressure to prepare an acoustically sound alternative space during the reconstruction of the Gaillard Performance Hall, which was the largest venue before its closing two years ago.

"We knew that when the Gaillard closed, the TD Arena would be a challenge for us audience-wise, especially with dance," Forster said. "We knew we may lose some revenue in terms of ticket sales for 2013 and 2014."

A 2010 economic report issued by Spoleto Festival USA reported that the festival brought in $44 million a year in tourism dollars, from hotel rooms to shopping to parking. "Spoleto attendees from outside of South Carolina spend more than $1,500 during their stay, which is nearly six times what the average South Carolina visitor spends," according to the report.

It also claimed that jobs generated during the period pumped $20.4 million into local household income.

Like many arts organizations, Spoleto has worked hard to identify key audience demographics. The 2010 report said the festival's audience primarily is made up of people 54 and older who are married and college educated, with an average household income of more than $130,000. A slight majority of Spoleto Festival's patrons are visitors.

Piccolo Spoleto, on the other hand, draws extensively from the local community.

Spoleto and Piccolo already are planning for 2015, and both are anticipating next spring's reopening of the Gaillard Performance Hall, which will have 1,800 seats.

Piccolo 2014 wraps up today with live music and food vendors at Hampton Park. Spoleto comes to a close in the traditional way, with live music at Middleton Place, featuring Shovels & Rope.

Angela Zonunpari and Olivia Yang are Goldring Arts Journalists from Syracuse University.