Gimme a break!!!
According to 2011 Bangladesh census your population was 142.3 million, increased to 158.9 million (as per above) over 4 years and Hindus were 12 million (as per 8.4% of 142.3). So, total increase of 16.6 million in 4 years, while Hindus increase by 5 million!!! So in 4 years total pop. increased by just 12%, while Hindus increased by 41%!!!.
This is already explained, Bangladeshi Hindus who have migrated to India have started to return to Bangladesh and some illegal Indians have also began to migrate to Bangladesh in search of jobs. SO the percentage has jumped up.