Definitions as of--	Separate metropolitan areas^/1	SMSAs outside SCAs and SCSAs; MSAs	SCAs; SCSAs; CMSAs	SMSAs inside SCAs and SCSAs; PMSAs	Total MAs defined	Component counties and county equivalents	Component New England cities and towns	Central cities
/1 Comprises SCAs and SCSAs and SMSAs outside of SCAs and SCSAs (1960, 1963, 1971, 1974, and 1981); also comprises MSAs and CMSAs (1983, 1990, 1992, and 1993). Excludes SMSAs within SCAs and SCSAs (1960, 1963, 1971, 1974, and 1981) and PMSAs (1983, 1990, 1992, and 1993). /2 Reflects all changes based on 1970 census data, the last of which occurred in August 1974; excludes certain changes based on 1973 and 1974 special census results. /3 SCA definitions included Middlesex and Somerset Counties, NJ, although they were not part of any SMSA; they are excluded from component counties totals. /4 Includes one American Indian reservation.
1950 census (March 1952; SMAs)	169	...	...	...	169	265	208	194

1960 census (November 1960; SMSAs,SCAs)	208	206	2^/3	6	214	335	265	257
1960 census updating (October 1963; SMSAs,SCAs)	212	210	2^/3	6	218	398	302	266

1970 census (February 1971; SMSAs,SCAs)	239	237	2^/3	6	245	452	310	308
1970 census updating (1974^/2; SMSAs,SCAs)	258	256	2^/3	8	268	622	378	361

1980 census (June 30, 1981;SMSAs,SCSAs)	286	270	16	48	334	696	430	429
1980 census updating (June 30, 1983; MSAs,CMSAs,PMSAs)	275	253	22	76	351	707	516^/4	507

1990 census (June 30, 1990; MSAs,CMSAs,PMSAs)	284	264	20	71	355	719	516^/4	525
1990 census updating (December 31, 1992; MSAs,CMSAs,PMSAs)	268	250	18	59	327	800	575^/4	524
1990 census updating (June 30, 1993; MSAs, CMSAs, PMSAs)	268	250	18	73	341	806	576^/4	532

Note: CMSA = Consolidated Metropolitan Statistical Area; MSA = Metropolitan Statistical Area; PMSA = Primary Metropolitan Statistical Area; SCA = Standard Consolidated Area; SCSA = Standard Consolidated Statistical Area; SMA = Standard Metropolitan Area; SMSA = Standard Metropolitan Statistical Area