how to find the growth rate of applicants per year

I have this data set with 20 variables, and I want to find the growth rate of applicants per year. The data provided is from 2020-2022. How would I go about that? I tried subsetting the data but I'm stuck on how to approach it. So essentially, I want 开发者_如何学Cto put the respective applicants to its corresponding year and calculate the growth rate.

Observations ID#   Date
 1           1226  2022-10-16
 2           1225  2021-10-15
 3           1224  2020-08-14
 4           1223  2021-12-02
 5           1222  2022-02-25

One option is to use lubridate::year to split your year-month-day variable into years and then dplyr::summarize().

library(tidyverse)
library(lubridate)
set.seed(123)

id <- seq(1:100)
date <- as.Date(sample( as.numeric(as.Date('2017-01-01') ): as.numeric(as.Date('2023-01-01') ), 100, 
                        replace = T), 
                origin = '1970-01-01')
df <- data.frame(id, date) %>%
  mutate(year = year(date))
head(df)
#>   id       date year
#> 1  1 2018-06-10 2018
#> 2  2 2017-07-14 2017
#> 3  3 2022-01-16 2022
#> 4  4 2020-02-16 2020
#> 5  5 2020-06-06 2020
#> 6  6 2020-06-21 2020

df <- df %>%
  group_by(year) %>%
  summarize(n = n())
head(df)
#> # A tibble: 6 × 2
#>    year     n
#>   <dbl> <int>
#> 1  2017    17
#> 2  2018    14
#> 3  2019    17
#> 4  2020    18
#> 5  2021    11
#> 6  2022    23