College degrees are getting more common nowadays. However most people do not go to college or obtain a bachelors degree. The numbers have risen considerably over the decades.
The Census of course has data on such things over the decades.
For all people age 25 or older the percent who finish high school and obtain a bachelors for each decade are as follows :
|(click image for larger version)|
Clearly over time people are obtaining higher level of education. Just about the same % of people in 2000 have Bachelors as the % who had High School diplomas back in 1940.
The Census also breaks the % figures down by age group. Here is the data for the different age groups for the % of people with Bachelors degrees:
|.25 years and over||4.6||6.2||7.7||10.7||16.2||20.3||24.4|
|..25 to 29 years||5.9||7.7||11.1||16.3||22.1||22.1||27.2|
|..30 to 34 years||6.3||7.4||10.9||14.4||24.6||23.4||27.9|
|..35 to 39 years||5.5||7.2||9.5||13.8||21.2||26.4||25.9|
|..40 to 44 years||4.7||7.4||8.1||12.4||17.5||27.7||25.9|
|..45 to 49 years||4.2||6.5||7.4||10.5||16.0||23.5||28.5|
|..50 to 54 years||3.8||5.6||7.3||8.8||13.9||19.4||29.1|
|..55 to 59 years||3.4||4.9||6.2||8.1||11.8||17.2||24.6|
|..60 to 64 years||3.3||4.3||5.0||7.9||10.0||14.9||20.3|
|..65 to 69 years||2.9||3.7||4.1||6.6||9.0||12.5||18.3|
|..70 to 74 years||2.6||3.6||3.6||5.5||9.0||10.6||16.2|
|..75 years and over||2.3||3.3||3.2||4.6||7.2||9.5||13.3|
You can see the peak as of 2000 was actually among the people age 50-54. This surprises me a little bit as I was assuming that the % of people with degrees would be lower with age in general. However if you give them a few more years the 20-30 year old group may start to take the lead.