set key reverse Left outside 

set term png 

set xtics rotate #we are going to rotate the "X" to get a vertical display

set output "Graph3.png"

set title "Growth in population between 1990 and 2010"	
set xlabel "Years ->" 					
set ylabel "Population by milion ->" 				

set offset 1,1,10,10 

plot 'Data3' using 1:2 title 'Week 1' with lines