The Crude Birth Rate (CBR), an important demographic indicator representing the number of live births per 1,000 people in a given year, has shown a significant decline over a five-year period. According to the Sample Registration System (SRS) data, the CBR has decreased from _____ in 2015 to _____ in 2020, reflecting improvements in family planning and health services.
1
21.0, 20.0
2
20.5, 19.8
3
20.8, 19.5
4
21.5, 20.5
5
22.0, 21.0