To facet your parliament plot, use the split-apply-combine strategy in a dplyr chain.

Steps

You must:

1) split by year 2) apply the coordinates for each party in parliament_data 3) combine the rows into one large data frame.

This can be done using map from purrr. A few examples are as follows:

American Congress from 2010 onwards

usa <- election_data %>%
  filter(country == "USA" &
    house == "Representatives")  %>% 
  split(.$year) %>% # split
  map(~parliament_data(election_data = ., # apply
  party_seats = .$seats,
  parl_rows = 8,
  type = "semicircle")) %>%
  bind_rows() # combine

us <- ggplot(usa, aes(x, y, colour = party_short)) +
  geom_parliament_seats() + 
  geom_highlight_government(government == 1) + 
  labs(colour = NULL, 
       title = "American Congress",
       subtitle = "The party that has control of US Congress is encircled in black.") +
  theme_ggparliament() +
  scale_colour_manual(values = usa$colour, 
                      limits = usa$party_short) + 
  theme(legend.position = 'bottom') + 
  facet_grid(~year, scales = 'free') 

us

Facet Australian Parliament by House

australia <- election_data %>%
  filter(country == "Australia" &
    year == "2016")  %>% 
  split(.$house) %>% # split
  map(~parliament_data(election_data = ., # apply
  party_seats = .$seats,
  parl_rows = 4,
  type = "horseshoe")) %>%
  bind_rows() # combine

au <- ggplot(australia, aes(x, y, colour=party_short, type = "horseshoe")) +
  geom_parliament_seats() + 
  geom_highlight_government(government == 1) + 
  labs(colour = NULL, 
       title = "Australian Parliament",
       subtitle = "Government encircled in black.") +
  scale_colour_manual(values = australia$colour, 
                      limits = australia$party_short) + 
  theme_ggparliament() +
  theme(legend.position = 'bottom') + 
  facet_grid(~house, scales = 'free')
#> Warning: Ignoring unknown aesthetics: type

au

Facet UK Parliament

uk<- election_data %>%
  filter(country == "UK")  %>%
  split(.$year) %>%
  map(~parliament_data(election_data = .,
  party_seats = .$seats,
  group = .$government,
  type = "opposing_benches")) %>%
  bind_rows()

ggplot(data = uk, 
       aes(x = x,
           y = y,
           color = party_long)) +
  geom_parliament_seats(size = 1.5) +  
  coord_flip() + 
  facet_wrap(~year, ncol = 2) + 
  scale_color_manual(values = uk$colour, 
                     limits = uk$party_long) +
  theme_ggparliament()