Costco investors have had much to celebrate this year as the company's first increase in membership fees in years seemed to do little to scare off customers during the fall.According to a quarter financial report released by Costco, the company ended November with 77.4 million paid memberships. The company had ended August with 76.2 million members. In the last year, Costco has added 5.4 million members.The growth in memberships came even as the company implemented a $5 increase in basic memberships and a $10 jump in executive memberships.With Costco earning much of its income off membership fees, the company has had a successful year for investors. The company's stock is up 52% since the start of 2024.RELATED STORY | Costco accused of unfair labor practices by Teamsters unionOne potential way the company has garnered some members is by strongly enforcing membership rules. The company has installed scanners at entrances in hopes of stopping customers from sharing memberships.Costco noted several records set over the previous quarter, including selling its highest number of pizzas in a single day on Halloween.To accommodate its growth in members, Costco said it plans to open 26 new locations in 2025.While Costco is known for selling food items in bulk, company leaders said new and unique products helped drive customer growth in the last year."That's part of the treasure hunt at Costco is always keeping nimble and continue to change those categories that we can find new areas to improve the lives of our members," said Ron Vachris, Costco CEO.