การส่งยานโดยรัฐ vs. เอกชน

# table of launches by year and agency type
launches_by_year <- launches %>% count(launch_year, agency_type)

# create a ShareData object for plotting
shared_launches <- launches_by_year %>% ___(key = ___)

# create a line chart displaying launches by agency type, with highlighting
shared_launches %>%
  ___(___, ___, ___) %>%
  ___() %>%
  ___()