I got to thinking about this very topic during those British bank commercials featuring Pete. In one, Pete says, "I had the all-time grand slam record on my racquet and I did it." In another, Pete asks, "Which man holds the all-time record of 288 consecutive weeks at #1? I do!" They seem kinda eeire...like someone knows Pete's window is closing more quickly than anyone would ever have imagined.
From the time Pete won his first slam ('90 USO) to the time he won his last at age 31 ('02 USO), Pete was winning slams at a clip of 1.14 per year.
If Roger plays 7 more years to age 31 (28 slams), he'd have to win at a clip of 1.29 slams per year to break Pete's record.
...6 years (age 30), it's 1.5, or 3 slams every two years for six years.