I prefer ratios.
Percentage of losses relative to weeks at #1.
Sub 20% loss rate with 300+ weeks.
Djokovic - 70/387 = 0.180 <20%
Sampras - 69/286 = 0.241
Federer - 56/310 = 0.181 <20%
Lendl. - 44/270 = 0.163
Nadal - 44/209 = 0.210