The complete report is a fee-based. You can view the table of contents and find ordering info here.
Detailed data tables from the report are available (free) on this page.
ARL Membership Totals (2010-2011)
115 University Libraries (16 in Canada and 99 in the US); the remaining 11 are public, governmental, and nonprofit research libraries (2 in Canada, 9 in the US).
Spending 2010-2011
From an ARL Announcement For 2010-2011 Report:
ARL libraries are a relatively small subset of libraries in North America, but they account for a large portion of academic library resources in terms of assets, budgets, and the number of users they serve. The total library expenditures of all 126 member libraries in 2010-2011 was slightly more than $4.6 billion; of that total, roughly $3.2 billion was spent by the 115 university libraries and more than $1.3 million by the 11 nonuniversity libraries.
Comparisons
2009-2010
The total library expenditures of all 125 member libraries in 2009–2010 was slightly more than $4.2 billion; of that total, roughly $3.2 billion was spent by the 115 university libraries and slightly more than $990 million by the 10 nonuniversity libraries.
2008-2009
The total library expenditures of all 124 member libraries in 2008–2009 was slightly more than $4 billion; of that total, roughly $3.1 billion was spent by the 114 university libraries and slightly more than $940 million the 10 nonuniversity libraries.