Also shown in Figure 2.3 is the funding for astronomy and astrophysics from NSF's Physics Division. This includes funding for theory, atomic and molecular astrophysics-related research, and submillimeter and IR astronomy from the South Pole. Further details are given in Chapter 5 . Inclusion of these programs would have resulted in astronomy and astrophysics support that was higher than that shown in Figures 2.2 and 2.3 . However, Figure 2.3 shows that the core funding of astronomy grants and facilities operation from NSF's Division of Astronomical Sciences has been relatively flat in constant FY 1997 dollars between 1990 and 1999.
Open diamonds show the number of grants funded annually, which has risen.
Figure 2.4 is an update of Figure B.4 of the 1991 Decadal Report and provides a more detailed view of the trends in grant funding. Since 1990, the average grant size appears to have stabilized. The 1991 Decadal Report made the further observation that the size of the average grant had dropped below the critical size required for support of a faculty summer salary plus a graduate student and travel. The consequence was that scientists often had to seek support from multiple grants, with a resultant increase in overhead for preparing, reviewing, and managing a larger number of smaller proposals. In the 1990s, astronomers appeared to turn increasingly toward NASA as a new source of funding to offset the dwindling size of NSF research grants.