ggplot2_百分比面積圖

year <- rep(1990:2015, times = 4)
type <- rep(c('A','B','C','D'),each = 26)
value <- c(runif(26),runif(26, min = 1,max = 1.5), 
           runif(26, min = 1.5,max = 2), 
           runif(26, min = 2,max = 2.5))
df <- data.frame(year = year, type = type, value = value)
ggplot(data = df, mapping = aes(x = year, y = value, fill = type)) + 
  geom_area(position = 'fill', alpha = 0.8) + 
  guides(fill = guide_legend(reverse = TRUE)) +
  theme(axis.title=element_blank(), 
        axis.text=element_blank(), 
        axis.ticks=element_blank())+ 
  guides(fill = FALSE, color = FALSE, linetype = FALSE, shape = FALSE, size = FALSE)  #刪除圖例