Registry of Open Access Repositories (ROAR)

The Registry of Open Access Repositories (ROAR) provide a useful service where they chart how many new entries there are in open access repositories. The information is presumably automatically extracted from the repository. As an example, for the ACS Digital Library:

ACS Digital Library (410 records)

Running Other softwares (various), based in Australia and is registered as e-Journal/Publication
Registered on 2006-12-05
Cumulative deposits: 410 total [table] [graph]
Daily deposits in last year: 1 days of 1-9, 1 days of 10-99, 0 days of 100+ [table] [graph (PNG format)] [interactive graph (requires SVG format support)]
OAI Interface: Identify List Metadata Formats List Sets [harvest status]
100% freely accessible fulltext (* estimate)

The ACS Digital Library provides international quality magazines, journal articles and conference papers, covering innovative research and practice in Information and Communications Technologies (ICT). This service is provided free to the ICT profession by the Australian Computer Society (ACS) as part of its commitment to ensure the beneficial use of technology for the community. It includes: Australasian Journal of Information Systems (AJIS), Journal of Research and Practice in Information Technology (JRPIT), and Conferences in Research and Practice in Information Technology (CRPIT).