library(directlabels)
library(ggplot2)
library(scales)
library(tidyr)

df = data.frame(Canada = c(522,	609,	611),
           US = c(15872, 17793, 19362),
           Mexico = c(20010, 20762, 24559))
df = data.frame(apply(df, 2, function(x) x = x/x[1]))
df$year = 2014:2016
df = tidyr::gather(df, country, percent, -year)
p = ggplot(df, aes(year, percent, group = country, color = country)) +
  geom_line() +
  xlab("year") +
  ylab("homicide count as a percentage of 2014") +
  scale_x_continuous(breaks = (2014:2016), limits = c(2014,2016.3)) +
  ggtitle("Homicides in Mexico, the US, and Canada 2014-2016 (2014 = 100%)" ,
          subtitle = "Sources: Statistics Canada, CANSIM, table 253-0001 and Homicide Survey, Canadian Centre for Justice Statistics, INEGI, and CDC Wonder") +
  theme_bw()  +
  scale_y_continuous(labels=percent)
directlabels::direct.label(p, "last.bumpup")