I would do it like this:

Row\Col
A
B
C
D
E
F
G
1
Country
Pop
%age
LUT
2
 China
90
0.900
0.000
 D2: =SUM(C1:D1)
0.227981061
 China
3
 India
10
0.100
0.900
0.204641412
 China
4
0.118028084
 China
5
0.333002558
 China
6
0.902475866
 India
7
0.579516928
 China
8
0.881442124
 China
9
0.695200101
 China
10
0.883110586
 China
11
0.363493999
 China
12
0.361990320
 China
13
0.524942046
 China
14
0.153411008
 China