• about 120 Astronomy Ph.D.'s are graduated per year from about 70 institutions (session 23--The Changing Shape of Graduate Education in Science). I believe this is North American Ph.D.'s only so the total number worldwide will be higher.
• from a survey of AAS members, 40% were tenured, 35% on soft money and 25% had "stable" funding, and more like 70% of members under 35 are on soft money. (session 64--Getting and Holding a Job with an Astronomy Degree).

Definitions:

• a postdoc position--a research position open to recent Ph.D.s with an expected duration of 5 years or less. Typical postdocs last about 2-3 years. 236 postdocs were advertised.
• faculty job -- a potentially permanent job. Anything described as a tenure-track job was included in this category. Also included are faculty, lectureship, professorial, directorate, and staff scientist positions at major government and private institutions which appear to be, but do not explicitly state, they are tenure-track or tenure-track equivalent. There were 85 positions advertised in this category, 51 explicitly stating they were tenure track. For some perspective, Pat Hall's job rumor page lists about 25 tenure track positions that are in contention. The true number of jobs undoubtably lies somewhere between these extremes.
• other research positions--sort of a catch all category. The only requirements for inclusion are that the position was not obviously a postdoc or a faculty position, that it required an astronomy Ph.D., and it allowed/ required research from the employee. These positions range from space support positions in industry renewable yearly to non-tenure track positions at major universities building instruments. The long term stability of positions in this category would seem to be highly variable. There were 77 positions advertized in this category.
• no astronomy Ph.D.--the final category was for jobs which did not require doctorate level astronomical reseach. For example, jobs not requiring a Ph.D. (often a B.S. or M.S.), astronomy support staff, jobs which required no astronomical research, and sabbatical jobs, were all included here. 66 positions in this category were advertised.

• I've assumed that 51 tenure track faculty position openings actually exist.
• A huge assumption lies with the number, duration, and stability of ``soft money" jobs, many of which are obtained directly by the researcher by writing grants and so are not advertised. Since the AAS membership has about equal numbers of people on soft money as people with tenure, and assuming a steady state situation, an equal number of soft money jobs should open as permanent, or about 51. This may be double accounting since some of these soft money positions may be postdocs. It is also not clear how many of these positions will open due to retirement (as presumably all tenured positions do in a no growth situation) and how many open due to someone leaving the field.
• The number of jobs in each category is stable, no increases or decreases. This is roughly consistent with the present and expected near future funding situation. Roughly.
• The number of jobs available is accurately reflected by the number advertised in the AAS Job Register and the last 12 months was a typical year. In reality some advertised jobs won't come through due to funding problems and other available jobs won't be advertised here. Last year also may not be typical due to large numbers of NICMOS and STIS postdocs.
• The total number of new Ph.D.s is 180 adjusting for Europe, Australia, etc. This seemed like a reasonable guess to me, but I have no data to back that up.
• The ``other research" category of jobs is encompassed in the soft money jobs numbers.

Postdoc job pool:

• gain 180 new Ph.D.s + 236 returning postdocs
• lose 51 to faculty and 51 to new soft money jobs
• 314 people apply for 236 jobs. 3 out of 4 applicants will get a job.
• Average number of postdocs per new Ph.D. = 1.3.

Leaving astronomy:

• 51 permanent positions open.
• 51 soft money positions open. 0 to 51 leave field before retirement.
• 180 new people enter. These squeeze 102 people into the more advanced jobs, and 78 others out.
• 78-129 people leave field before retirement (43-71% of those entering).

If you have better figures or more realistic estimates of any of my guesses, or have thought of something I haven't, let me know. If you want to be really depressed, see Thronson, 1991, PASP, 103, 90, whose quote is featured on my career resources page.