With just a few weeks left of 2015, live music fans are already anticipating the slew of major tours that will kick off in 2016, including Justin Bieber's Purpose World Tour, Rihanna's long-awaited Anti World Tour, and of course, Adele's major North American tour in support of 25. While tickets for these tours are expected to skyrocket into the New Year, tickets to see Adele may be on track to be the most expensive so far, as her December 17 on-sale generated huge demand on the secondary market, with resale tickets now averaging $1,397. Although it seems likely that some of these tours will set new milestones for ticket prices and gross incomes, 2015 presented a handful of tours that will be hard to top, including Taylor Swift's insanely popular 1989 World Tour, One Direction's final On The Road Again tour run, U2's epic iNNOCENCE + eXPERIENCE tour and The Grateful Dead'Fare Thee Well run. Ticket aggregator TiqIQ breaks down each of the top tours from 2015 below:

(Photo : TiqIQ)

Taylor Swift | 1989 World Tour | May 15-October 31 | Average Ticket Price: $373

Unless you've been living under a rock this year, it has been nearly impossible to avoid hearing about Taylor Swift. The pop princess began her massive 1989 World Tour back in May, and it ran until Halloween night in the U.S. The tour hit major stops in Los Angeles, East Rutherford and Miami. Tickets to Swift's five consecutive nights at L.A.'s Staples Center averaged well over $600, and her October 27 stop in Miami at The American Airlines Arena averaged an insanely expensive $1225, with the cheapest ticket available being $383. Part of the tour's massive draw was the rotating cast of celebrity guests that Swift enlisted for each date. All-star appearances included Justin Timberlake, Selena Gomez, Jason Derulo and even the U.S. Women's National Soccer team. According to Billboard, the tour had already grossed a massive $173 million in early October, making it an unforgettable run.

One Direction | On The Road Again | July 9-September 12 | Average Ticket Price: $215

Although the ever-popular British boyband took a blow to their solidarity earlier in the year when Zayn Malik dropped out of the group, the guys still managed to trek on with one of the hottest summer runs. Their On The Road Again Tour launched in the U.S. on July 9 and ran until September 12. Tickets for the tour averaged a solid $215 across of their North American dates, with the biggest demand in Indianapolis at the Lucas Oil Stadium, where tickets averaged $413 with the cheapest tickets available for $46. Although the tour failed to meet the same demand that their 2014 Where We Are Tour did (it grossed over $200 million), On The Road Again was a solid final run for the boys.

U2 | iNNOCENCE + eXPERIENCE | Dates: May 13-July 31 | Average Ticket Price: $294

U2 is known for selling concert tickets, so it should come as no surprise that the Irish band's iNNOCENCE + eXPERIENCE tour was a big seller this year. Across all of their U.S. dates, U2 tickets averaged an impressive $294, with huge demand in big cities. The band's massive eight-date residency at New York City's Madison Square Garden was enormous, averaging $439 with the cheapest ticket available for all nights at just $74. The bands last stop of the night at MSG on July 31 averaged $668. The band's prior tour "U2 360," which ran from 2009-2011, grossed a total of $736.4 million and moved 7.2 million tickets, Billboard reported. iNNOCENCE + eXPERIENCE clocked in significantly less than U2 360 with $76 million in total. However, this summer's tour hit significantly smaller venues, and ran for a much shorter period of time. Despite the comparison, U2 still drove one of the hottest tours of 2015, reaching millions of fans across the map.

Grateful Dead | Fare Thee Well | Dates: May 27-28, July 3-5 | Average Ticket Price: $436

This year, legendary band The Grateful Dead grouped up to play six farewell shows to celebrate the band's 50 year anniversary. The "core four" played two weekends with the help of Phish guitarist and legend Trey Anastasio. The first batch of shows was held in their hometown of Santa Clara, California at the Levi's Stadium, and the final batch was played on July 3-5 at Soldier Field in Chicago. Tickets were extraordinarily expensive for both. At the time, the band declared the shows would be their final ever, despite the separate incarnation of the band (Dead & Co) that went on to tour with John Mayer this fall. Tickets for Fare Thee Well averaged a whopping $436 across the scheduled dates, with the highest demand on July 3, where a ticket averaged $706. In total, the band's weekend in Chicago grossed an impressive $30 million. The tour was a momentous one for music, as it closed a chapter for one of the biggest bands of all time.

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