# This code is based on the replication material of
# Mitchell et al. (2020): "What We Know (and Could Know) About 
# International Environmental Agreements" doi:10.1162/glep_a_00544
# made available under 
# https://iea.uoregon.edu/ieadb_article_online_appendix
# iea_replication/Stata13/iea.dat
# converted from Stata file format to csv using R library "haven"

# read data
ieas <- read.csv("iea.csv",as.is=TRUE)

# use only multilateral agreements (as in ieadb-graph.do)
ieas <- subset(ieas,inclusion == "MEA")

# all years and all years that have a running 5-year mean value
allyrs <- (min(ieas$tsig_yr)):(max(ieas$tsig_yr))
allmeanyrs <- (min(ieas$tsig_yr)+2):(max(ieas$tsig_yr)-2)
# factor treaties by year, compute total number per year
byyrs <- factor(ieas$tsig_yr,allyrs)
bytype <- factor(ieas$agreement_type)
freqPerYr <- tapply(ieas$tsig_yr,byyrs,length,default=0,simplify=TRUE)
# factor by year and type, and add total number per year as column
freqPerYrAndType <- cbind( table(byyrs,bytype), freqPerYr)

colors <- c("blue","red","green","black")
typeNames <- c("Übereinkommen","Protokoll","Änderung","Summe")
linetypes <- c(2,3,4,1)
linewidths <- c(3,3,3,1.5)

xrange=range(allmeanyrs)
yrange=c(1,40)

# prepare plot
plot(xrange,yrange,type="n",
     main="Abgeschlossene multilaterale Umweltabkommen\n1857–2017",
     xlab="Jahr",ylab="Anzahl pro Jahr",
     lab=c(9,9,0), # approx. number of x and y ticks
     col="black", # plotting color
     fg="darkgray")  # color of axis
grid(col="lightgray", lty="dotted",lwd=1, equilogs=TRUE)

# compute and plot 5-yr running means
for (i in 1:length(typeNames)) {
  data <- filter(freqPerYrAndType[,i], rep(0.2, 5), sides = 2)
  lines(allmeanyrs,data[3:(length(data)-2)],col=colors[i],lwd=linewidths[i],lty=linetypes[i])
}

legend("topleft", typeNames, fill=colors, cex=0.75,title=" gleitende 5-Jahres-Mittel: ")
text(2040,-17,"Daten:\nRonald B. Mitchell, 2002–2020, IEADB",adj=1,pos=2,cex=0.75,xpd=TRUE)