The below data depicts depicts how the catorgy of guests on The Daily Show changed over time. We can see for example how the frequency of actors decline.

actorsgrouped <- guests %>% 
    group_by(YEAR,guest_category) %>%
    summarize(count = n())%>% 
    filter(guest_category == 'Acting')
## `summarise()` regrouping output by 'YEAR' (override with `.groups` argument)
actorsgrouped
## # A tibble: 17 x 3
## # Groups:   YEAR [17]
##     YEAR guest_category count
##    <int> <chr>          <int>
##  1  1999 Acting           108
##  2  2000 Acting           100
##  3  2001 Acting            92
##  4  2002 Acting            84
##  5  2003 Acting            74
##  6  2004 Acting            51
##  7  2005 Acting            44
##  8  2006 Acting            44
##  9  2007 Acting            25
## 10  2008 Acting            26
## 11  2009 Acting            22
## 12  2010 Acting            45
## 13  2011 Acting            42
## 14  2012 Acting            33
## 15  2013 Acting            60
## 16  2014 Acting            47
## 17  2015 Acting            33

While the frequency of politician guests increased and remianed steady around 2004.

journalistgrouped <- guests %>% 
    group_by(YEAR,guest_category) %>%
    summarize(count = n())%>% 
    filter(guest_category == 'Politician')
## `summarise()` regrouping output by 'YEAR' (override with `.groups` argument)
journalistgrouped
## # A tibble: 17 x 3
## # Groups:   YEAR [17]
##     YEAR guest_category count
##    <int> <chr>          <int>
##  1  1999 Politician         2
##  2  2000 Politician        13
##  3  2001 Politician         3
##  4  2002 Politician         8
##  5  2003 Politician        14
##  6  2004 Politician        32
##  7  2005 Politician        22
##  8  2006 Politician        25
##  9  2007 Politician        21
## 10  2008 Politician        27
## 11  2009 Politician        26
## 12  2010 Politician        25
## 13  2011 Politician        23
## 14  2012 Politician        29
## 15  2013 Politician        11
## 16  2014 Politician        13
## 17  2015 Politician        14

The most prononced in the progression of guests coming from the media.

mediagrouped <- guests %>% 
    group_by(YEAR,guest_category) %>%
    summarize(count = n())%>% 
    filter(guest_category == 'Media')
## `summarise()` regrouping output by 'YEAR' (override with `.groups` argument)
mediagrouped
## # A tibble: 17 x 3
## # Groups:   YEAR [17]
##     YEAR guest_category count
##    <int> <chr>          <int>
##  1  1999 Media             11
##  2  2000 Media             21
##  3  2001 Media             30
##  4  2002 Media             39
##  5  2003 Media             41
##  6  2004 Media             45
##  7  2005 Media             54
##  8  2006 Media             47
##  9  2007 Media             47
## 10  2008 Media             77
## 11  2009 Media             59
## 12  2010 Media             50
## 13  2011 Media             50
## 14  2012 Media             52
## 15  2013 Media             51
## 16  2014 Media             53
## 17  2015 Media             24