RLI 280 Research Library Trends: A Historical Picture of Services, Resources, and Spending 23 SEPTEMBER 2012 RESEARCH LIBRARY ISSUES: A QUARTERLY REPORT FROM ARL, CNI, AND SPARC data will no longer be tied to format (serials or monographs). It is important to track expenditures for continuing resources as they make libraries vulnerable to monopolistic tendencies, but it is clear that “serials” are morphing into a variety of different online products and services. Figure 3. Supply and Demand in ARL Libraries, 1986–2011 -25% 0% 25% 50% 75% 100% 125% 150% 175% 200% 225% 250% 275% 300% 2010 2007 2004 2001 1998 1995 1992 1989 1986 Monographs Purchased (+10%) Faculty (+30%) Total Students (+46%) Graduate Students (+139%) Interlibrary Lending (+102%) Interlibrary Borrowing (+280%) % Change Since 1986 Figure 3 shows that interlibrary borrowing and lending, which experienced a marked growth from 1986 to 2006, are now steadily declining, likely due to the wide availability of information resources. Overall research libraries continue to lend more than they borrow, indicating the rich and unique level of resources available at these institutions, thus supporting their mission to serve researchers beyond their institutional boundaries.