grouping_by_condition_and_mutate in R

Question

I need your help:

The general idea is to create 1 new column, Group the data by a column (DEP) then count the number of Total lines per group using the column (id).

Then filter the data with another column (dely): (only dely>=60) and count the id

Then calculate the share using the number of rows of (the filtered columns)/ (total number calculated at the beginning).

total= count(id by group)

share = (dely>=60)/total

I was able to do it in 3 steps but I wanted to know if possible to do it in a faster way?

#group the data by ( DEP)

Total_group<-df %>%
  group_by(DEP) %>%
  summarise(n = n())

filter the data T_depart>60

Filter_60<- df %>% filter(df$T_depart>=60)

#then gorup the filtred data by DEP as I did for the Total

Filter_60_group<-Filter_60 %>%
group_by(DEP) %>%
summarise(n = n())

share_data<-left_join (Total_group, Filter_60_group, by="DEP") %>%  mutate(share_dep=n.x/n.y)

Any idea how to put all this steps in one or 2 step?