How to center value vertically on each subsection of a single stacked bar plot in ggplot2?

I want to create a stacked bar plot with a single bar, and I would like that each value is shown on the graph, in the middle of the corresponding section.

This enter image description hereis what I get and I have no idea on how to move them. It's weird because they are upside down too.

This is my code:

sk <- sk %>% 
  pivot_longer(cols = c(A, B,C, D, E, F), 
               names_to = "Variable", values_to = "Value")

sk <- sk %>%
  group_by(Variable) %>%
  mutate(cumulative = cumsum(Value) - (Value / 2))

ggplot(data = sk, aes(x = variable, y = Value, fill = Variable)) +
  geom_bar(position = "stack", stat = "identity") +
  xlab("") + ylab("") +
  theme_minimal() +
  theme(legend.position = "right") +
geom_text(aes(y = cumulative, label = Value))

You don't need to try to work out the cumulative position of the stacked labels. Simply put position = position_stack(vjust = 0.5) inside your geom_text call.

Also note that geom_bar(stat = "identity") is just a long way of writing geom_col:

library(tidyverse)

sk %>% 
  pivot_longer(cols = c(A, B, C, D, E, F), 
               names_to = "Variable", values_to = "Value") %>%
  ggplot(aes(x = "", y = Value, fill = Variable)) +
  geom_col(position = "stack") +
  geom_text(position = position_stack(vjust = 0.5), aes(label = Value)) +
  labs(x = NULL, y = NULL) +
  theme_minimal() 

I might also point out that from both a data viz and aesthetic point of view, a stacked single bar isn't the best way to show your data here. Compare, for example:

sk %>% 
  pivot_longer(cols = c(A, B, C, D, E, F), 
               names_to = "Variable", values_to = "Value") %>%
  ggplot(aes(x = Variable, y = Value, fill = Variable)) +
  geom_col() +
  geom_text(aes(label = Value), nudge_y = 2) +
  labs(x = NULL, y = NULL) +
  theme_minimal() +
  theme(legend.position = 'none')

Which is tidier, easier to read, easier to interpret and nicer to look at.

Data approximation inferred from image in question

sk <- data.frame(A = 38, B = 226, C = 752, D = 1692, E = 3045, F = 5977)/100