Dữ liêu tham khảo:

Mar,2012 50
Apr,2012 49.5
May,2012 48.3
Jun,2012 46.6
Jul,2012 43.6
Aug,2012 47.9
Sep,2012 49.2
Oct,2012 48.7
Nov,2012 50.5
Dec,2012 49.3
Jan,2013 50.1
Feb,2013 48.3
Mar,2013 50.8
Apr,2013 51
May,2013 48.8
Jun,2013 46.4
Jul,2013 48.5
Aug,2013 49.4
Sep,2013 51.5
Oct,2013 51.5
Nov,2013 50.3

Theo HSBC.
Dec,2013 51.8