The following is a very rough representation of the growth of astronomical research since 1970 based on the contents of the 'Astronomy and Astrophysics Abstracts':
Year Keywords Papers Authors Journals ....................................................................... 1970 6350 7018 166 1972 6300 6771 288 1974 6300 7312 291 1976 6690 8283 426 1978 8300 9245 634 1980 8935 10288 791 1982 8436 9740 656 1984 2273 10956 9774 1986 2305 10392 12223 1988 2354 11559 13610 1990 2388 11423 14461 1992 2447 10063 13723 1994 2493 11665 15635 ......................................................................
The table is not complete, but I think you can see the trends. By the way, the totals for 1990 - 1994 only represent the period from January to October of each year. Multiply these numbers by 12/10 = 1.2 to get annual totals for 1990, 1992 and 1994 to put them on the same basis as the other totals for 1970 - 1988. In 10 years, the number of keywords has grown by 10 percent, the number of papers has almost doubled, as has the number of astronomers publishing their research. Essentially, the more people you have working in a field, the more papers and discoveries you will make. Not all discoveries are of equal significance however!