Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | 1948 | 1952 | 1956 | 1960 | 1964 |
| --- | --- | --- | --- | --- | --- |
| all voters | 50 | 45 | 42 | 50 | 61 |
| White | 50 | 43 | 41 | 49 | 59 |
| Black | 50 | 79 | 61 | 68 | 94 |
| College educated | 22 | 34 | 31 | 39 | 52 |
| High School educated | 51 | 45 | 42 | 52 | 62 |
| Grade School educated | 64 | 52 | 50 | 55 | 66 |
| Professional & Business | 19 | 36 | 32 | 42 | 54 |
| White Collar | 47 | 40 | 37 | 48 | 57 |
| Manual worker | 66 | 55 | 50 | 60 | 71 |
| Farmer | 60 | 33 | 46 | 48 | 53 |
| Union member | 76 |  | 51 | 62 | 77 |
| Not union | 42 |  | 35 | 44 | 56 |
| Protestant | 43 | 37 | 37 | 38 | 55 |
| Catholic | 62 | 56 | 51 | 78 | 76 |
| Republican |  | 8 | 4 | 5 | 20 |
| Independent |  | 35 | 30 | 43 | 56 |
| Democrat |  | 77 | 85 | 84 | 87 |
| East | 48 | 45 | 40 | 53 | 68 |
| Midwest | 50 | 42 | 41 | 48 | 61 |
| West | 49 | 42 | 43 | 49 | 60 |
| South | 53 | 51 | 49 | 51 | 52 |
Question:
how many groups are listed in the year 1948?
Answer:
17