stacked area chart

R code of the ggplot2 example

library(ggplot2)
library(dplyr)
library(gapminder)

## Oceania, two countries, would be a band too thin to name.
population <- gapminder |>
  filter(continent != "Oceania") |>
  group_by(continent, year) |>
  summarise(pop = sum(pop) / 1e9, .groups = "drop")

## Each name goes after the middle of its band, in 2007; the last level is
## stacked at the bottom.
ends <- population |>
  filter(year == max(year)) |>
  arrange(desc(continent)) |>
  mutate(y = cumsum(pop) - pop / 2)

p <- ggplot(population, aes(x = year, y = pop, fill = continent)) +
  geom_area(colour = "white", linewidth = 0.3) +
  geom_text(data = ends, aes(x = year, y = y, label = continent, colour = continent),
            hjust = 0, nudge_x = 1.5, size = 3.5) +
  scale_x_continuous(breaks = seq(1952, 2007, 10), expand = expansion(mult = c(0, 0.2))) +
  scale_y_continuous(labels = lex_number, expand = expansion(mult = c(0, 0.05))) +
  scale_fill_manual(values = continent_colors) +
  scale_colour_manual(values = continent_text_colors) +
  labs(title = "Population more than doubled from 1952 to 2007",
       subtitle = "140 countries, summed by continent; Oceania left out",
       x = NULL, y = "Population (billions)",
       caption = "Data: Gapminder, via the gapminder R package") +
  theme_lex_viz(grid = "y") +
  theme(legend.position = "none")