I don't know why but when I run ggplot stacked area chart, years on the x-axis are doubles like 2012.5.... I set them as integer but still have this issue. Any solution?

```
df$Year <- as.integer(df$Year)

order <- df %>% filter(Year ==max(df$Year) ) %>% arrange(desc(Sales)) %>% select(Category)
df$Category <- factor(df$Category, levels = order$Category)

df %>% 
  ggplot(aes(x = Year, y = Sales, fill = Category)) +
  geom_area()

```

[![enter image description here](https://i.stack.imgur.com/wbqhC.png)](https://i.stack.imgur.com/wbqhC.png)