Other major changes under Oaks included implementing a three-semester plan with full fall and winter semesters, and a split spring and summer term. This also shifted the end of the fall term to before Christmas. Oaks also oversaw a large-scale celebration of the BYU centennial. During his tenure at BYU, enrollment grew twenty percent; the average class size was maintained at thirty-four students. Library holdings increased to 2 million and the number of faculty members with doctorate degrees increased to 22 percent. The number of buildings constructed per year decreased to eight per year, compared to eleven per year during Wilkinson's administration. Church appropriations increased from $19.5 million to $76 million, making up approximately one-third of the university's income. Spending increased from $60 million to $240 million. Under the realization that faculty salaries were considerably low compared to other colleges in the western United States, BYU periodically increased the salary of employees, particularly female employees. Even with the raising of salaries, BYU faculty salaries were still about $1,000 less than other universities and colleges in the region. University income was bolstered by donations and fund-raising. In the mid-1960s, the university decided to name buildings after people who donated more than $500,000 to the university. The first building constructed entirely from private donations was the N. Eldon Tanner Building.