1. Archive size and data downloads over time

2. Growth of the HEASARC Archive

3. Demand for HEASARC Web services

4. Citations of selected HEASARC missions

5. Data requests by quarter

6. Data transferred by TB and by equivalent numbers of datasets, broken down by mission, for selected years

7. History of Data Transfers by Mission

8. Detailed HEASARC Usage Statistics (Internal Access only)

Click on any figure below to see an enlarged, printable version.

Archive Size and Data Downloads over Time
	Figure 1: HEASARC high-energy archive size & annual data download volume plotted over time: note that the y-axis scale is logarithmic. Back to top

Growth of the Archive
	Figure 2: Past 25 years growth of the size of the HEASARC high-energy astrophysics data archive. Back to top

Demand for HEASARC Web Services
	Figure 3: Demand for HEASARC Web Services: Annual numbers of SkyView images requested, Browse queries submitted, volume of high-energy science web pages downloaded, and volume of high-energy science data downloaded. Back to top

Citations of Selected HEASARC Missions
	Figure 4: Number of citations of selected HEASARC missions over time. Back to top

High-energy astrophysics data and web pages downloaded from the HEASARC
	Figure 5: FTP and HTTP requested volume of data and web pages (TB per quarter). Back to top

Transfer rates
	Figure 6(a): The amount of high-energy data downloaded in 2021, broken down by mission.
	Figure 6(b): The number of (equivalent) high-energy datasets downloaded in 2021, broken down by mission. Back to top
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Data Holdings
	Figure 7: HEASARC high-energy & CMB data holdings as of Dec 2021, broken down by mission. These totalled 163 TB. Back to top
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