ggplot2: Add secondary x label (year below months)

Question

My Problem is related to: Axis labels on two lines with nested x variables (year below months)

However, my data looks a little different.

library(dplyr)

set.seed(122)
df <- as_tibble(rlnorm(1260, meanlog = 0.06, sdlog = 0.20))

df$month <- rep(c("Jan", "Feb", "Mär", "Apr", "Mai", "Jun", 
      "Jul", "Aug", "Sep", "Okt", "Nov", "Dez"), 5, each=21)

df$year <- rep(c("Year 1", "Year 2", "Year 3", "Year 4", "Year 5" ), 1, each=252)

I would like my line graph too look like this, but without the vertical line if possible:

Answer 1

library(tidyverse)

#data:
set.seed(122)
df <- as_tibble(rlnorm(1260, meanlog = 0.06, sdlog = 0.20))
#> Warning: Calling `as_tibble()` on a vector is discouraged, 
#> because the behavior is likely to change in the future. 
#> Use `tibble::enframe(name = NULL)` instead.

df$month <- rep(c("Jan", "Feb", "Mär", "Apr", "Mai", "Jun", 
                  "Jul", "Aug", "Sep", "Okt", "Nov", "Dez"), 5, each=21)

df$year <- rep(c("Year 1", "Year 2", "Year 3", "Year 4", "Year 5" ), 1, each=252)

#solution:
month_lab <- rep(unique(df$month), length(unique(df$year)))

year_lab <- unique(df$year)

df %>%
  as.data.frame() %>%
  rename(price = 1) %>% 
  mutate(rnames = rownames(.)) %>% 
  ggplot(aes(x = as.numeric(rnames), y = price, 
             group = year)) +
  geom_line() +
  labs(title = "Stock Price Chart", y = "Price", x = "date") +
  scale_x_continuous(breaks = seq(1, 1260, by = 21), 
                     labels = month_lab, expand = c(0,0)) +
  facet_grid(~year, space="free_x", scales="free_x", switch="x") +
  theme(strip.placement = "outside",
        strip.background = element_rect(fill=NA,colour="grey50"),
        panel.spacing=unit(0,"cm"))

^{Created on 2019-05-28 by the reprex package (v0.3.0)}