Occupation	years	Total
Total	2001	46,465
Total	2000	47,055
Total	1999	38,323
Total	1998	34,667
Total	1997	30,023
Total	1996	29,431
Total	1995	27,557
Total	1994	27,321
Total	1993	27,781
Total	1992	28,590
Total	1991	29,151
Total	1990	28,508
Total	1989	25,865
Total	1988	23,678
Total	1987	20,361
Total	1986	19,007
Total	1985	16,860
Total	1984	15,022
Total	1983	12,905
Total	1982	12,914
Total	1981	12,006
Total	1980	12,303
Total	1979	11,911
Total	1978	11,591
Total	1977	..
Total	1976	14,175
Total	1975	13,199
Total	1974	11,311
Total	1973	9,937
Total	1972	8,686
Total	1971	7,623
Total	1970	5,691
Total	1969	4,777
Researchers	2001	18,959
Researchers	2000	20,869
Researchers	1999	15,178
Researchers	1998	13,902
Researchers	1997	12,009
Researchers	1996	11,100
Researchers	1995	10,803
Researchers	1994	11,070
Researchers	1993	11,256
Researchers	1992	11,593
Researchers	1991	11,622
Researchers	1990	11,007
Researchers	1989	9,394
Researchers	1988	8,552
Researchers	1987	6,835
Researchers	1986	6,160
Researchers	1985	4,853
Researchers	1984	4,019
Researchers	1983	3,528
Researchers	1982	3,409
Researchers	1981	3,226
Researchers	1980	2,994
Researchers	1979	2,950
Researchers	1978	2,800
Researchers	1977	..
Researchers	1976	3,002
Researchers	1975	2,760
Researchers	1974	2,683
Researchers	1973	2,340
Researchers	1972	1,981
Researchers	1971	1,681
Researchers	1970	1,426
Researchers	1969	1,164
Technicians	2001	18,738
Technicians	2000	17,039
Technicians	1999	15,103
Technicians	1998	12,516
Technicians	1997	11,178
Technicians	1996	10,932
Technicians	1995	9,992
Technicians	1994	9,133
Technicians	1993	9,287
Technicians	1992	9,440
Technicians	1991	9,510
Technicians	1990	9,137
Technicians	1989	8,601
Technicians	1988	7,608
Technicians	1987	6,559
Technicians	1986	6,222
Technicians	1985	5,556
Technicians	1984	4,627
Technicians	1983	3,884
Technicians	1982	4,049
Technicians	1981	3,727
Technicians	1980	3,549
Technicians	1979	2,978
Technicians	1978	2,864
Technicians	1977	..
Technicians	1976	3,762
Technicians	1975	..
Technicians	1974	3,059
Technicians	1973	2,627
Technicians	1972	1,472
Technicians	1971	1,240
Technicians	1970	943
Technicians	1969	791
Assistants	2001	8,768
Assistants	2000	9,147
Assistants	1999	8,042
Assistants	1998	8,249
Assistants	1997	6,836
Assistants	1996	7,400
Assistants	1995	6,763
Assistants	1994	7,118
Assistants	1993	7,238
Assistants	1992	7,557
Assistants	1991	8,019
Assistants	1990	8,364
Assistants	1989	7,870
Assistants	1988	7,518
Assistants	1987	6,967
Assistants	1986	6,625
Assistants	1985	6,451
Assistants	1984	6,376
Assistants	1983	5,494
Assistants	1982	5,456
Assistants	1981	5,053
Assistants	1980	5,760
Assistants	1979	5,983
Assistants	1978	5,927
Assistants	1977	..
Assistants	1976	7,411
Assistants	1975	..
Assistants	1974	5,569
Assistants	1973	4,970
Assistants	1972	5,233
Assistants	1971	4,702
Assistants	1970	3,322
Assistants	1969	2,822