of CASM-Ex growth at less than 2% annually. Fleet restructuring is an important component of our cost initiatives and is focused on lowering unit costs while enhancing the customer experience. We are restructuring our domestic fleet by replacing a significant portion of our 50-seat regional flying with more efficient and customer preferred CRJ-900 and B-717-200 aircraft and replacing older, less cost effective B-757-200 aircraft with B-737-900ER aircraft. During the year ended December 31, 2014, we took delivery of 26 CRJ-900, 39 B-717-200 and 19 B-737-900ER aircraft. We are retiring a significant portion of the 50-seat regional fleet that we lease as part of the fleet restructuring activities. We expect to continue to recognize restructuring charges, representing the remaining obligations under the leases, as we retire the leased aircraft. Although many factors could change over the period of the 50-seat fleet restructuring, we currently estimate that future charges will be between $50 million to $150 million. As a result of restructuring the fleet, we expect to benefit from improved operational and fuel efficiency, customer service and reduced future maintenance cost that we will experience over the life of the new aircraft.  

 

SkyMiles Program  

 

During the March 2014 quarter, we announced changes to the SkyMiles program. Effective January 1, 2015, the SkyMiles program was modified from a model in which customers earn redeemable mileage credits based on distance traveled to a model based on ticket price. Customers earn between five and 11 miles per dollar spent based on their SkyMiles status, and will continue to earn up to an additional two miles per dollar when using their Delta SkyMiles Credit Card, for a total of up to 13 miles per dollar. The modified program will better reward customers who spend more with Delta and give them improved mileage-earning opportunities. The SkyMiles program includes a new award redemption structure that improves award seat availability at the lowest point redemption levels, offers one-way awards at half the price of round-trip, provides new miles plus cash award options, as well as makes significant improvements to delta.com and Delta reservations award shopping tools.  



Results of Operations - 2014 Compared to 2013  

 

Operating Revenue  

Passenger Revenue

Passenger revenue increased $2.0 billion , or 6% , over prior year. PRASM increased 3% and passenger mile yield increased 2% on 3% higher capacity. Load factor was 0.9 points higher than prior year at 84.7% .  

 

Our geographic regions generally performed well compared to the prior year, with the domestic region leading year-over-year unit revenue improvement. Unit revenues of the domestic region rose 8% led by strong performances from our hubs in Atlanta, New York-LaGuardia and Seattle.  

 

Revenues related to our international regions increased 3% year-over-year primarily due to 18% capacity growth in the Latin America region as a result of our efforts to improve connections with GOL and Aeroméxico. GOL and Aeroméxico contributed a significant portion of the traffic from the U.S. to Brazil and into key Mexico markets, respectively.