Table:
year
sunday times rich list
forbes the world's billionaires

rank
net worth (gb£) bn
rank
net worth (us$) bn

2005
none
none
3
$25.00

2006
1
£14.88
5
$23.50

2007
1
£19.25
5
$32.00

2008
1
£27.70
4
$45.00

2009
1
£10.80
8
$19.30

2010
1
£22.45
5
$28.70

2011
1
£17.50
6
$31.10

2012
1
£12.70
21
$20.70

2013
4
£10.00
41
$16.50

2014
3
£10.25
52
$13.70

2015
7
£9.20
82
$13.50

2016
11
£7.12
135
8.4

Statement: in 2016, forbes listed mittal as the 135th-wealthiest billionaire, with a net worth of us$8.4 billion.
Question: in 2016, what was a net worth did forbes list mittal as the 135th-wealthiest billionaire, with a net worth of?
Answer: [8.4]