Himachal Pradesh has a total population of 6,864,602 including 3,481,873 males and 3,382,729 females as per the final results of the Census of India 2011. This is only 0.57 per cent of Indias total population, recording a growth of 12.81 per cent. The scheduled castes and scheduled tribes account for 25.19 per cent and 5.71 per cent of the population respectively. The sex ratio stood at 972 females per 1000 males, recording a marginal increase from 968 in 2001. The child sex ratio increased from 896 in 2001 to 909 in 2011. The total fertility rate (TFR) per woman in 2015 stood at 1.7, one of the lowest in India.
Question: How many more females were there per 1000 males in 2001 compared to 2011?
Answer: 4