Ggplot percent multiplied by 100

Question

I want to use ggplot to make a graph showing percentages on yaxis. here is the data and code that I used

data<-"yrs.1.17 yrs.18.44 yrs.45.64 yrs.65.84 yrs.85.
1     4.53     35.12     32.93     22.86    4.57
2     4.01     34.74     34.19     22.71    4.34
3     4.75     33.23     35.19     22.28    4.51
4     4.60     34.04     36.93     20.70    3.56
5     4.80     33.82     37.69     19.97    3.52
6     4.30     35.09     37.08     19.83    3.65
7     3.65     38.08     36.19     19.18    2.85
8     3.72     38.11     36.10     19.22    2.86"

mydata<- read.table(text=data, header=TRUE)


year<-c(2006,2007,2008,2009,2010,2011,2012,2013)
df<-data.frame(year,mydata)
library(ggplot2)
library(reshape2)
library(scales)
newdf<-melt(df,'year')
ggplot(newdf,aes(x=year,y=value,group=variable,color=variable))+ geom_line(size=1)+
scale_x_continuous(breaks=year)+xlab("Year")+scale_y_continuous(labels = percent,limits=c(1,50),breaks=seq(5,50,by=5))+ylab("Age groups")+
geom_point(aes(shape=variable),size=3)+
ggtitle("Age groups of people between 2006 and 2013")+
theme(legend.title=element_blank(), legend.justification=c(0.6,0.6), legend.position=c(0.95,0.95), legend.text = element_text(size=9), 
axis.text = element_text(size=9), axis.title = element_text(size=9), plot.title=element_text(size = 9))     

As you can see in the output, percentages are multiplied by 100. Is there a way to get the right percentages.
Many thanks.

Answer 1

Just divide by 100:

ggplot(newdf,
  aes(
    x = year,
    y = value / 100, # here divide by 100
    group = variable,
    color = variable
  )
) + 
  geom_line(size=1)+
  scale_x_continuous(breaks=year) + 
  xlab("Year") + 
  scale_y_continuous(
    labels = percent,
    limits = c(.01, .5),            # here divide by 100
    breaks = seq(.05, .5, by = .05) # here divide by 100
  ) +
  ylab("Age groups") +
  geom_point(aes(shape = variable), size=3) +
  ggtitle("Age groups of people between 2006 and 2013") +
  theme(legend.title=element_blank(),
        legend.justification = c(0.6, 0.6),
        legend.position = c(0.95, 0.95),
        legend.text = element_text(size = 9), 
        axis.text = element_text(size = 9),
        axis.title = element_text(size = 9),
        plot.title = element_text(size = 9)) 

As a side note, and not for all manual settings element_text(size = 9), most topics take an argument base_size, so using theme_grey(9)or theme_classic(9)will do most of the work for you. You may still need to change the title.