This is just a reprex of a thing that I couldn't replicate on Stack Overflow https://stackoverflow.com/questions/34860535/how-to-use-dplyr-to-generate-a-frequency-table/34860724

dplyrReprex

library(tidyverse)
#> Warning: package 'tidyverse' was built under R version 3.4.4
#> -- Attaching packages ----------------------------------------------------------------------------------------------- tidyverse 1.2.1 --
#> v ggplot2 3.0.0     v purrr   0.2.4
#> v tibble  1.4.2     v dplyr   0.7.6
#> v tidyr   0.8.1     v stringr 1.3.0
#> v readr   1.1.1     v forcats 0.3.0
#> Warning: package 'ggplot2' was built under R version 3.4.4
#> Warning: package 'tibble' was built under R version 3.4.4
#> Warning: package 'readr' was built under R version 3.4.4
#> Warning: package 'purrr' was built under R version 3.4.4
#> Warning: package 'dplyr' was built under R version 3.4.4
#> Warning: package 'stringr' was built under R version 3.4.4
#> Warning: package 'forcats' was built under R version 3.4.4
#> -- Conflicts -------------------------------------------------------------------------------------------------- tidyverse_conflicts() --
#> x dplyr::filter() masks stats::filter()
#> x dplyr::lag()    masks stats::lag()

x = "RespondentID    Color        Gender   
1     1503          Red           F      
2     1653          NA            M   
3     1982          Red           F   
4     4862          Red           NA   
15    4880          Blue          M"

df = read.table(text = x, header = TRUE)

gather(df, "var", "value", -RespondentID) %>%
  count(var, value) %>%
  mutate(prop = prop.table(n))
#> Warning: attributes are not identical across measure variables;
#> they will be dropped
#> Warning: package 'bindrcpp' was built under R version 3.4.4
#> # A tibble: 6 x 4
#>   var    value     n  prop
#>   <chr>  <chr> <int> <dbl>
#> 1 Color  Blue      1   0.1
#> 2 Color  Red       3   0.3
#> 3 Color  <NA>      1   0.1
#> 4 Gender F         2   0.2
#> 5 Gender M         2   0.2
#> 6 Gender <NA>      1   0.1