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. Results from HEASARC Users Survey (completed in Jan 2019)

9. 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 24 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 2018, broken down by mission.
	Figure 6(b): The number of (equivalent) high-energy datasets downloaded in 2018, broken down by mission. Back to top
The 44 Terabytes of HEASARC data transferred in 2009 broken down by mission/directory. The number of datasets (100,131) transferred in 2009 broken down by mission/directory. The 28.88 Terabytes of HEASARC data transferred in 2007 broken down by mission/directory. The number of datasets (64,351) transferred in 2007 broken down by mission/directory. The number of datasets transferred in 2005 by mission/directory. The number of datasets transferred in 2004 by mission/directory. The number of gigabytes transferred in 2003 by mission/directory (top) and datasets transferred in 2003 by mission (bottom). The number of gigabytes transferred in all of 2001 by mission/directory. The number of gigabytes transferred in all of 2000 by mission/directory. The number of gigabytes transferred in all of 1998 by mission/directory. Back to top

Data Holdings
	Figure 7: HEASARC high-energy & CMB data holdings as of Nov 2018, broken down by mission. These totalled ~116 TB. Back to top
HEASARC data holdings as of October 2007, broken down by mission. These totalled 16.4 TB. HEASARC data holdings as of October 2005, broken down by mission.These totalled 7.6 TB. HEASARC data holdings as of November 2003, broken down by mission.These totalled 3.2 TB. HEASARC data holdings as of November 2001, broken down by mission. These totalled 2.4 TB. HEASARC data holdings as of December 2000, broken down by mission. These totalled 2.2 TB. HEASARC data holdings as of December 1999, broken down by mission. These totalled 1.7 TB. HEASARC data holdings as of January 1999, broken down by mission. These totalled 1.4 TB. HEASARC data holdings as of March 11, 1998, broken down by mission. These totalled 0.96 TB. Back to top