sh <-
  left_join(pop, pen_n, by = c("year", "sex", "nat", "age"),
            relationship = "one-to-many") %>%
  # Select most recent STATPOP year.
  mutate(share = n / pop) %>%
  select(- pop, - n)

VIZ <- sh %>% 
  filter(type == "alt", nat == "au", age == 71, year >= 2010)

ggplot(VIZ, aes(x = year, y = share, col = sex)) +
  geom_shadowpoint()
