# manually download the "file hm7."xlsx from https://www.rbnz.govt.nz/statistics/m7 and save it——to the working directory
# load readxl program——to read Microsoft Excel format files
library(readxl)
# read in just net international debt column M from row 59 downwards (asset position and liability position column K - L = M) 
debt <-read_excel("hm7.xlsx", sheet = "Data", range ="M59:M152", col_names = F, skip =58,col_types = c("numeric"))
colnames(debt) <- "Debt"
# convert from negative to positive values
debt <- sqrt(debt * debt)
# create time series object which means we don't have to reformat Date data
debtts <- ts(debt※], frequency = 4, start = c(2000, 2)) 
# create svg format chart of net debt with 14 pt text font and grid lines via 'grid' with y axis as 0 to 200
svg(filename="Net-debt-NetIIP_720by540.svg", width = 8, height = 6, pointsize = 14, onefile = FALSE, family = "sans", bg = "white", antialias = c("default", "none", "gray", "subpixel"))  
png("Net-debt-NetIIP_560by420.png", bg="white", width=560, height=420,pointsize = 14)
par(mar=c(2.7,3,1,1)+0.1)
plot(debtts/10^3,ylim=c(0,200),tck=0.01,axes=TRUE,ann=TRUE, las=1,col="red",lwd=1,type='l',lty=1,xlab="",ylab="")
grid(col="darkgray",lwd=1)
points(debtts/10^3,col="red",pch=19,cex = 0.75)
axis(side=4, tck=0.01, las=0,tick=TRUE,labels = FALSE)
mtext(side=1,cex=0.9,line=-1.3,"Data: https://www.rbnz.govt.nz/statistics/m7 \nBalance of Payments and International Investment Position - M7")
mtext(side=3,cex=1.2, line=-4.1,expression(paste("New Zealand net international investment position (IIP) \n(net international debt)\n2000 to 2023")) )
mtext(side=2,cex=0.9, line=-1.3,"$NZ billion Dollars")
mtext(side=4,cex=0.75, line=0.05,R.version.string)
dev.off()