Only 42.7% of mothers were breastfeeding their babies six to eight weeks after birth, according to Public Health England (PHE) data for 2017/18 in England.
In 2016/17 the figure stood at 44.4%, according to PHE.
Data from NHS England show that the rate was 43.1% in 2015/16, and 43.8% for 2014/15.
Breastfeeding rates also varied significantly by region.
Eight in 10 babies were being breastfed at this age in Tower Hamlets in London compared to less than one in five (18.9%) in Knowsley, Merseyside.
The World Health Organisation recommends that mothers should exclusively breastfeed their babies for the first six months of life.
After babies start eating solid foods at six months of age, officials suggest continued breastfeeding up to the age of two and beyond.
Meanwhile the NHS Start for Life website adds that there are many advantages of breastfeeding, including health benefits for both babies and mothers.
Breast milk protects babies from infections and provides a “perfect balance” of vitamins and nutrition for infants, according to the website.
Breastfed babies have a lower chance of cot death and childhood leukaemia, they also have a lower risk of allergies and are less likely to develop diabetes or become overweight when they are older.
Benefits for women include reducing their risk of breast cancer, ovarian cancer, osteoporosis, diabetes and cardiovascular disease.
Previous research has estimated that 5% of breast cancer cases in the UK are caused by not breastfeeding.