data %>%
mutate(y=case_when(
          y >= 2 ~ "high",
          y  < 2 & y >= 1 ~ "medium",
          y  < 1 ~ "low")) %>%
mutate_all(as.factor) %>%
mutate(y = factor(y, levels = c("low", "medium", "high"))) %>%
group_by(y, x, z) %>%
count() %>%
group_by(x, z) %>%
mutate(prop = n / sum(n)) %>%
ggplot(aes(x = z, y = prop, fill = y)) +
  geom_col() +
  geom_text(aes(label = scales::percent(prop)),
                position = position_fill(vjust = 0.5),
                size = 3) +
  facet_grid(x~.) +
  scale_fill_brewer(palette = "RdYlBu") +
  theme_minimal() +
    labs(y = "")

plot1<-ggplot(data,aes(x = z, y = prop, fill = y)) +
      geom_col() +
      geom_text(aes(label = scales::percent(prop)),
                    position = position_fill(vjust = 0.5),
                    size = 3) +
      facet_grid(x~.) +
      scale_fill_brewer(palette = "RdYlBu") +
      theme_minimal() +
        labs(y = "")
plot1

Error in eval(expr, envir, enclos) : object 'prop' not found

library(tidyverse)

data <- data.frame(año=c(2012,2012,2012,2012,2013),
                   delito=c("posesion", "comercio", "trafico", "venta", "venta"),
                   enero=c(13,2,12,15,17), febrero=c(1,2,4,3,5), marzo=c(8,8,8,9,10))

data %>%
    gather(clave, valor, -`año`, -delito) %>%
    spread(delito, valor)

spread(
    gather(data,
           clave,
           valor,
           -`año`,
           -delito
           ),
    delito,
    valor)