The data were compiled by Nielsen SoundScan based collectively on each single's weekly physical (CD, vinyl and cassette) and digital sales, airplay, and streaming.
While Santana's "Smooth" featuring Rob Thomas topped the chart in the first two weeks of 2000, it was not counted as a number-one single of the 2000s decade by Billboard because it had topped the chart in October 1999, and thus was counted as a number-one single of the 1990s decade only.
[4] Overall, the decade saw the dominance of hip hop and R&B releases with dance beats and pop crossover, replacing the 1990s' trend of sentimental ballads.
[6] Note: The best-performing singles on the Billboard Hot 100 of 2000 and 2001 were Faith Hill's "Breathe" and Lifehouse's "Hanging by a Moment", respectively.
Rihanna's "Umbrella" featuring Jay-Z, for example, was counted for both artists because they are both credited on the single.