I am working with the R programming language. I downloaded the following data on world populations and tried to make a histogram:

```
#data source: https://population.un.org/wpp/Download/Files/1_Indicators%20(Standard)/CSV_FILES/WPP2019_TotalPopulationBySex.csv
`WPP2019_TotalPopulationBySex.(1)` <- read.csv("C:/Users/ME/Downloads/WPP2019_TotalPopulationBySex (1).csv")
world_data = WPP2019_TotalPopulationBySex.(1)
> head(world_data)
LocID Location VarID Variant Time MidPeriod PopMale PopFemale PopTotal PopDensity
1 4 Afghanistan 2 Medium 1950 1950.5 4099.243 3652.874 7752.117 11.874
2 4 Afghanistan 2 Medium 1951 1951.5 4134.756 3705.395 7840.151 12.009
3 4 Afghanistan 2 Medium 1952 1952.5 4174.450 3761.546 7935.996 12.156
4 4 Afghanistan 2 Medium 1953 1953.5 4218.336 3821.348 8039.684 12.315
5 4 Afghanistan 2 Medium 1954 1954.5 4266.484 3884.832 8151.316 12.486
6 4 Afghanistan 2 Medium 1955 1955.5 4318.945 3952.047 8270.992 12.669
world_data$PopMale = as.numeric(substr(world_data$PopMale,1,1))
world_data$PopFemale = as.numeric(substr(world_data$PopFemale,1,1))
world_data$PopTotal = as.numeric(substr(world_data$PopTotal,1,1))
world_data$PopDensity = as.numeric(substr(world_data$PopDensity,1,1))
```

I tried to make the histogram:

```
library(ggplot2)
library(scales)
library(cowplot2)
g1 = ggplot(world_data, aes(x=PopMale)) + geom_histogram() + + ggtitle("Male Population")
g2 = ggplot(world_data, aes(x=PopFemale)) + geom_histogram() + ggtitle("Female Population")
g3 = ggplot(world_data, aes(x=PopTotal)) + geom_histogram() + ggtitle("Total Population")
g4 = ggplot(world_data, aes(x=PopDensity)) + geom_histogram()+ ggtitle("Population Density")
plot_row = plot_grid(g1, g2, g3, g4)
# now add the title
title <- ggdraw() +
draw_label(
"World Population: Does Benford's Law Exist?",
fontface = 'bold',
x = 0,
hjust = 0
) +
theme(
# add margin on the left of the drawing canvas,
# so title is aligned with left edge of first plot
plot.margin = margin(0, 0, 0, 7)
)
plot_grid(
title, plot_row,
ncol = 1,
# rel_heights values control vertical title margins
rel_heights = c(0.1, 1)
)
```

**Question:** I am trying to format the x-axis of the histograms so that they display integers (e.g. 0,1,2,3,4,5,6,7,8,9). I tried to use the following code to do this:

```
integer_breaks <- function(n = 5, ...) {
fxn <- function(x) {
breaks <- floor(pretty(x, n, ...))
names(breaks) <- attr(breaks, "labels")
breaks
}
return(fxn)
}
library(ggplot2)
g1 = ggplot(world_data, aes(x=PopMale)) + geom_histogram() + scale_x_continuous(breaks = integer_breaks()) + ggtitle("Male Population")
g2 = ggplot(world_data, aes(x=PopFemale)) + geom_histogram() + scale_x_continuous(breaks = integer_breaks() + ggtitle("Female Population")
g3 = ggplot(world_data, aes(x=PopTotal)) + geom_histogram() + scale_x_continuous(breaks = integer_breaks() + ggtitle("Total Population")
g4 = ggplot(world_data, aes(x=PopDensity)) + geom_histogram()+ scale_x_continuous(breaks = integer_breaks() + ggtitle("Population Density")
plot_row = plot_grid(g1, g2, g3, g4)
# now add the title
title <- ggdraw() +
draw_label(
"World Population: Does Benford's Law Exist?",
fontface = 'bold',
x = 0,
hjust = 0
) +
theme(
# add margin on the left of the drawing canvas,
# so title is aligned with left edge of first plot
plot.margin = margin(0, 0, 0, 7)
)
plot_grid(
title, plot_row,
ncol = 1,
# rel_heights values control vertical title margins
rel_heights = c(0.1, 1)
)
```

**Problem:** But this is still displaying the x-axis as before.

Can someone please show me how to fix this problem?

Thanks!