Yahoo Sport 
10 things to know about the women’s Rolex Rankings, which debuted on this day in 2006
The Rolex Rankings debuted less than 20 years ago on Feb. 21, 2006. For context, the men’s Official World Golf Ranking has been around since 1986.
In that time, 18 different women from nine different countries have risen to the top, giving fans from all over the world reason to celebrate.
The rankings are used to fill fields at the majors, determine teams like the Solheim Cup and International Crown and decide which top players qualify for the Olympics.
Both amateurs and professionals are eligible and the rankings are updated every Monday.
Here are 10 interesting things to note about the Rolex Rankings, which are now 18 years old:
Who was the first World No. 1?
It should come as no surprise that Annika Sorenstam, the greatest player of the modern era, topped the first edition of the Rolex Rankings. Sorenstam remained there for 60 weeks before being overtaken by Lorena Ochoa.
How do the rankings work?
The rankings award points based on field strength (with the exception of the five majors, which are fixed) and a player’s performance over a rolling two-year period, with more weight placed on the most recent 13 weeks. A minimum divisor (35) is also used.
Players are ranked based on their average points per tournament, which is determined by dividing the total number of points by the number of eligible tournaments played during the 104-week period.
Who has been No. 1 the longest?
Jin Young Ko holds the record for the longest time at No. 1 with 163 weeks over the course of five different stretches. Lorena Ochoa was No. 1 for 158 weeks and Lydia Ko for 125.
Who is the youngest to reach No. 1?
Lydia Ko became the youngest player to reach No. 1 at 17 years, 9 months, 9 days on Feb. 2, 2015.
Who had the longest stretch at No. 1?
Lorena Ochoa spent 158 consecutive weeks at No. 1, right up until she retired in 2010.
Who spent the shortest total time at No. 1
Atthaya Thitikul first rose to No. 1 on Oct. 31, 2022. She spent two weeks on top before Nelly Korda knocked her off. Thitikul hasn’t yet made it back there.
Which country has the most weeks at No. 1?
Five South Korean players have spent a whopping 333 weeks on top of the world (Jiyai Shin, Inbee Park, So Yeon Ryu, Sung Hyun Park and Jin Young Ko).
By contrast, four U.S. players (Cristie Kerr, Stacy Lewis, Nelly Korda and Lilia Vu) have been No. 1 a total of 91 weeks.
Who is the current No. 1?
Lilia Vu first became No. 1 on Aug. 14 of last year. Currently in her third stretch as the world’s top player, she’s been No. 1 for a total of 24 weeks.
Which country dominates the top 100?
South Korean players have dominated the top 100 since the rankings debuted. Last year, 32 South Koreans finished inside the top 100, down from a high of 41 both in 2013 and 2017.
