I was looking for the same and this may also work
p.Wages.all.A_MEAN <- Wages.all %>%
group_by(`Career Cluster`, Year)%>%
summarize(ANNUAL.MEAN.WAGE = mean(A_MEAN))
names(p.Wages.all.A_MEAN) [1] "Career Cluster" "Year" "ANNUAL.MEAN.WAGE"
p.Wages.all.a.mean <- ggplot(p.Wages.all.A_MEAN, aes(Year, ANNUAL.MEAN.WAGE , color= `Career Cluster`))+
geom_point(aes(col=`Career Cluster` ), pch=15, size=2.75, alpha=1.5/4)+
theme(axis.text.x = element_text(color="#993333", size=10, angle=0)) #face="italic",
p.Wages.all.a.mean