Hotel transaction volumes are set to reach $25 billion this year, with private equity firms, offshore investors and real estate investment trusts accounting for the bulk of the sales activity, according to experts at Jones Lang LaSalle’s Hotels & Hospitality Group. Five straight years of growth in revenue per available room have also led to an increase in high-priced hotel sales — the average per-room price of hotel transactions in the first five months of 2014 is up 15 percent from a year ago.