Actually, the numbers I gave are the usual averages. Read enough sociology to know where the cohorts range.
Millenials are called as such because the cohort is usually those born before 2000 but became adults after 2000.
all from wiki
Baby boomers (also known as
boomers) are the
demographic cohort following the
Silent Generation and preceding
Generation X. There are varying timelines defining the start and the end of this cohort; demographers and researchers typically use starting birth years ranging from
the early-to mid-1940s and ending birth years ranging from 1960 to 1965
Generation X or
Gen X is the
demographic cohort following the
baby boomers and preceding the
Millennials. There are no precise dates for when Generation X starts or ends. Demographers and researchers typically use birth years ranging from the
early-to-mid 1960s to the early 1980s.
Millennials, also known as Generation Y or Gen Y, are the generational demographic cohort following Generation X and preceding Generation Z. There are no precise dates for when this cohort starts or ends; demographers and researchers typically use the early 1980s as starting birth years and the mid-1990s to early 2000s as ending birth years.
I've never heard once a cohort of millenials starting in the 1970's. There's no such study that I have came upon. All millenial cohorts I've seen start at minimum in 1980.