This was 9.1 percent lower than the state average of 40.9 percent. In 2020 the total municipality population reached 2,314.
89.2 percent of the population had at least a high school diploma or the equivalent.
Degree distribution in Custer for 2020*
| Degree | Number of people | Percentage of population |
|---|---|---|
| No degree | 202 | 10.8 |
| Regular high school diploma | 562 | 30 |
| GED or alternative credential | 89 | 4.7 |
| Some college, less than 1 year | 91 | 4.9 |
| Some college, 1 or more years, no degree | 334 | 17.8 |
| Associate's degree | 121 | 6.5 |
| Bachelor's degree | 326 | 17.4 |
| Master's degree | 106 | 5.7 |
| Professional school degree | 26 | 1.4 |
| Doctorate degree | 18 | 1 |

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