R 为什么向ggplot添加geom_文本会更改图例线型？

我正在绘制一个数字，显示不同年龄组的个人健康状况的平均值。我展示了在两个不同时期接受采访的两组人之间的差异：2006-08和2009-12。正如您在下面的两个图中所看到的，一旦我将geom_文本添加到代码中，图例线型就会改变。有人能告诉我如何在添加geom_文本的同时保持它的实体和虚线吗

以下是没有geom_文本的绘图：

ggplot(df, aes(age, mean_health, linetype= Year, color= Year))+
  geom_line()

ggplot(df, aes(age, mean_health, linetype= Year, color= Year))+
  geom_line()+
  geom_text(data = filter(a, mean_health == max(a$mean_health[Year == "2009-12"])), 
                  aes(age, mean_health, label = round(mean_health, 0)), hjust = 1.20, vjust=0, size=4)

以下是带有geom_文本的绘图：

ggplot(df, aes(age, mean_health, linetype= Year, color= Year))+
  geom_line()

ggplot(df, aes(age, mean_health, linetype= Year, color= Year))+
  geom_line()+
  geom_text(data = filter(a, mean_health == max(a$mean_health[Year == "2009-12"])), 
                  aes(age, mean_health, label = round(mean_health, 0)), hjust = 1.20, vjust=0, size=4)

以下是我的数据：

structure(list(age = c(18, 18, 19, 19, 20, 20, 21, 21, 22, 22
), Year = structure(c(1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), .Label = c("2006-08", 
"2009-12"), class = "factor"), mean_health = c(85.8131067961165, 
87.0587925403013, 84.7693574958814, 86.5121248004943, 84.5478434971219, 
86.1607839060144, 84.0793845077811, 85.5619426238315, 83.6882757389053, 
85.0810204193354), mean_chr = c(9.0427240603919, 8.95552835577315, 
9.70889575540738, 9.31401831939466, 9.82768571193009, 9.45283585075522, 
10.5885398688298, 9.52824332712601, 9.979633401222, 9.86532875627145
)), row.names = c(NA, -10L), groups = structure(list(age = c(18, 
19, 20, 21, 22), .rows = structure(list(1:2, 3:4, 5:6, 7:8, 9:10), ptype = integer(0), class = c("vctrs_list_of", 
"vctrs_vctr", "list"))), row.names = c(NA, 5L), class = c("tbl_df", 
"tbl", "data.frame"), .drop = TRUE), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"))

---

据我所知，ggplot为每个几何图形创建了一个图例。。。因此，这些小的（有时是恼人的）“a”出现了。有几个选项可以隐藏图例。将

show.legend=FALSE

添加到geom_uz-调用中可能是最简单的：

 ...
geom_text(aes(...label = round(mean_health, 0)),..., show.legend = FALSE)
...