大家可以把空气质量烟草等等数据加进去比较一下。

数据：
# http://www.phic.org.cn/tonjixinxi/weishengtongjijianbian/

year heart brain respiratory
2005 133.68 132.92 53.07
2006 124.12 123.83 51.36
2007 135.36 130.83 58.83
2008 141.36 133.98 59.83
2009 146.40 133.44 57.72
2010 156.97 142.29 60.92
2011 146.00 128.59 62.14
2012 150.84 129.01 59.39
2013 156.60 131.98 57.92

gnuplot:
set terminal svg
set output 'beijing.svg'
set yrange [0:200]
set grid ytics
set xlabel "year"
set ylabel "1/100k"
plot 'beijing.dat' using 1:2 with linespoints title 'heart', \
'beijing.dat' using 1:3 with linespoints title 'brain', \
'beijing.dat' using 1:4 with linespoints title 'respiratory'

result:
https://jsfiddle.net/fq80q2gt/

simple normalization

set terminal svg
set output 'beijing_1.svg'
#set yrange [0:1]
set grid ytics
set xlabel "year"
set ylabel "relative 1/100k"
plot 'beijing.dat' using 1:(($2-100)/100) with linespoints title 'heart', \
'beijing.dat' using 1:(($3-100)/100) with linespoints title 'brain', \
'beijing.dat' using 1:(($4-50)/50) with linespoints title 'respiratory'

result:
https://jsfiddle.net/x61xve0x/embedded/result/