r - Reproduce a 'The Economist' chart with dual axis

Question

I was trying to replicate this chart from The Economist (the one on the left). The chart plots the number of billionaires in Russia on the left y-axis and the number of billionaires in rest of the world on the right.

1. Create the chart for Russian billionaires (p1).
2. Create the chart for the others (p2).
3. Combine p1 and p2 into a dual y-axis chart using the code by Kohske.

Data: (content of billionaire.csv)

,Russia,World
1996,0,423
1997,4,220
1998,1,221
1999,0,298
2000,0,322
2001,8,530
2002,6,466
2003,17,459
2004,25,562
2005,27,664
2006,33,760
2007,53,893
2008,87,1038
2009,32,761
2010,62,949
2011,101,1109
2012,96,1130
2013,110,1317
2014,111,1535
2015,88,1738

Code:

library(ggplot2)
library(gtable)
library(grid)
library(extrafont) # for Officiana font
dat <- read.csv("billionaire.csv")
rus <- dat[,1:2]
world <- dat[,-2]

grid.newpage()
p1 <- ggplot(rus, aes(X, Russia)) + geom_line(colour = "#68382C", size = 1.5) + ggtitle("Number in Russia") +
  ylim(0, 200) + labs(x="",y="") +
  theme(#plot.margin = unit(c(2,1,0,0), "cm"),
    panel.grid.minor = element_blank(), 
    panel.grid.major = element_line(color = "gray50", size = 0.5),
    panel.grid.major.x = element_blank(),
    text=element_text(family="ITCOfficinaSans LT Book"),
    axis.text.y = element_text(colour="#68382C", size = 14),
    axis.text.x = element_text(size = 14),
    axis.ticks = element_line(colour = 'gray50'),
    plot.title = element_text(hjust = -0.17, vjust=2.12, colour="#68382C", size = 14, family = "ITCOfficinaSans LT Bold")) 

p2 <- ggplot(world, aes(X, World)) + geom_line(colour = "#00a4e6", size = 1.5) +  #ggtitle("Rest of world") +
  ylim(0, 2000) + labs(x="",y="") +
  theme(#plot.margin = unit(c(2,1,0,0), "cm"),
    panel.grid.minor = element_blank(), 
    panel.grid.major = element_blank(),
    text = element_text(family="ITCOfficinaSans LT Book"),
    axis.text.y = element_text(colour="#00a4e6", size=14),
    axis.text.x = element_text(size=14),
    axis.ticks = element_blank(),
    plot.title = element_text(hjust = 0.2, vjust=2.12, colour="#00a4e6", size = 14, family = "ITCOfficinaSans LT Bold"))

# Combining p1 and p2
g1 <- ggplot_gtable(ggplot_build(p1))
g2 <- ggplot_gtable(ggplot_build(p2))

pp <- c(subset(g1$layout, name == "panel", se = t:r))
g <- gtable_add_grob(g1, g2$grobs[[which(g2$layout$name == "panel")]], pp$t, 
                             pp$l, pp$b, pp$l)

ia <- which(g2$layout$name == "axis-l")
ga <- g2$grobs[[ia]]
ax <- ga$children[[2]]
ax$widths <- rev(ax$widths)
ax$grobs <- rev(ax$grobs)


g <- gtable_add_cols(g, g2$widths[g2$layout[ia, ]$l], length(g$widths) - 1)
g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b)
ggsave("plot.pdf",g, width=5, height=5)

To format the texts "Number in Russia" and "Rest of the world" with my chosen font and color, I put them in ggtitle. But after combining the charts together in step 3 the title of p2 is missing, so this is all I got

What I'm trying to achieve is
1. Add the text "Rest of world" in a color and font family of my choice (not the default Helvetica.)
2. Add the label 1996 on the x-axis.

Any help is appreciated. Thanks!

EDIT: Data set and full code added.
EDIT2: Just FYI, I got all the Officiana fonts from here: http://people.oregonstate.edu/~hanshumw/Specie%20I.D./Signage%20Backup/FONT%20Officina%20full/
EDIT3: Ok I finally how to make it work by fiddling with the plot at the grid level

g$grobs[[8]]$children$GRID.text.526$label <- c("Number in Russia", "Rest of World")
g$grobs[[8]]$children$GRID.text.526$gp$col <- c("#68382C","#00a4e6")
g$grobs[[8]]$children$GRID.text.526$x <- unit(c(-0.175, 0.774), "npc")

Put this chunk before ggsave(...), and here's the result:

Answer 1

Here's a solution using R base graphics, rather than ggplot. I didn't change the font family, as that's only portable across systems with the same fonts installed (I don't have Officiana here). It's easy to add a family argument to mtext to do so.

par(mar = c(3, 3, 3, 3), las = 1)
plot(tmp[,c(1,3)], type = 'n', axes = FALSE, ylim = c(0, 2000))
abline(h = c(0, 500, 1000, 1500, 2000), col = "grey")
points(tmp[,c(1,3)], type = 'l', col = "blue", lwd = 2)
points(x = tmp[,1], y = tmp[,2] * 10, type = 'l', col = "brown", lwd = 2)
axis(side = 4, at = c(0, 500, 1000, 1500, 2000), tick = FALSE,
     col.axis = "blue", line = 1, hadj = 1)
axis(side = 2, at = c(0, 500, 1000, 1500, 2000), tick = FALSE,
     col.axis = "brown", hadj = 1,
     labels = c(0, 50, 100, 150, 200))
axis(side = 1, at = c(1996, 2000, 2005, 2010, 2015), lwd = 0, line = -1,
     lwd.ticks = 2, col.ticks = "grey")
mtext("Number in Russia", side = 2, col = "brown", at = 2150, line = 2.5,
      adj = 0)
mtext("Rest of World", side = 4, col = "blue", at = 2150, line = 2,
      adj = 1)