From Billboard.com:


Britney Spears' Sustained Success 'Go'-es On At Pop Radio
by Gary Trust | September 12, 2011 5:35 EDT
In a format known for its rapid-fire artist turnover and constant search for the next sonic fad, Britney Spears' sustained success at pop radio has reached new heights.
Spears claims the mark for the longest span of No. 1s on Billboard's Pop Songs chart, as "I Wanna Go" rises 2-1 on the Nielsen BDS-based mainstream top 40 radio airplay tally.
Spears scored the first of her six No. 1s on the chart the week of Feb. 20, 1999, with "...Baby One More Time." With this week's listing dated Sept. 24, she extends her stretch of leading the list to a record 12 years, seven months and four days.