Growth of $1 Chart using ggplot2

dollar_growth_chart.R

# LOAD LIBRARIES
require(quantmod)
require(ggplot2)

# GET DATA, CONVERT TO DATA FRAMES
getSymbols("VBMFX", from = "1990-01-01", to = Sys.Date(), adjust = TRUE)
getSymbols("VFINX", from = "1990-01-01", to = Sys.Date(), adjust = TRUE)
vbfmx <- data.frame(VBMFX, date = index(VBMFX))
vfinx <- data.frame(VFINX, date = index(VFINX))

# SET PLOT THEME OPTIONS
plain <- opts(
  panel.grid.major = theme_blank(), 
  panel.grid.minor = theme_blank(),
  plot.background  = theme_rect(fill = 'gray95', colour = NA),
  panel.background = theme_blank(),
  plot.title = theme_text(face = 'bold', hjust = 0, size = 24, vjust = 1) 
)

# PLOT IT!!
qplot(date, VFINX.Open/VFINX.Open[1], data = vfinx, geom = 'line', colour = I('maroon')) + 
  geom_line(data = vbfmx, aes(y = VBMFX.Open/VBMFX.Open[1]), colour = 'deepskyblue3') +
  geom_hline(yintercept = seq(1, 6, 1), colour = 'gray80') +
  xlab('') + ylab('') +
  opts(title = 'Cumulative Growth since 1991') +
  plain