The annual rate of decline is around half that recorded in the previous 12 months - between 2014/15 and 2015/16 adoptions fell 12 per cent.
Adoptions have been falling since late 2013, following a ruling by Sir James Munby in the case of Re B-S in which he criticised the "sloppy practice" of social workers and said that local authorities must provide evidence that all alternatives to adoption had been considered before bringing a case to court.
The latest board figures also show the number of children waiting to be placed with an adoptive family rose over the final three months of 2016/17.
At the end of March 2017, there were 2,470 children waiting to be adopted, a seven per cent increase on the 2,320 waiting at the end December 2016.
This follows falls of three per cent in the third quarter, eight per cent in the second quarter and 10 per cent in the first quarter of the year.
In 2016/17, 34 per cent of adoption approvals were made by councils within six months, compared with 30 per cent the previous year.
In addition, the average time between a placement order being issued and a match with a child made was six months, compared with eight months the previous year.
Over the course of the year the number of people approved as adopters also fell 17 per cent - from 3,610 in 2015/16 to 2,980 in 2016/17.
However, registrations to become an adopter increased by 27 per cent from 750 between October and December 2016 to 950 in January to March 2017.
Overall, the number of registrations in 2016/17 fell by two per cent compared with 2015/16.