Sex ratio refers to the :

Number of females per 1000 males in a given area at a specified time period.

The sex ratio refers to the number of females per 1000 males in a given area at a specified time period..

The sex ratio is an important indicator of gender balance in the population. Historically, the sex ratio has been slightly in favour of females, that is, the number of females per 1000 males has generally been somewhat higher than 1000. However, India has had a declining sex-ratio for more than a century. From 972 females per 1000 males at the turn of the twentieth century, the sex ratio has declined to 933 at the turn of the twenty-first century. The trends of the last four decades have been particularly worrying – from 941 in 1961 the sex ratio had fallen to an alltime low of 927 in 1991 before posting a modest increase in 2001. According to Census of India 2011 sex ratio has increased and now it is 943 females per 1000 males.