What's the 70/30 rule in golf?

What's the 70/30 rule in golf has several interpretations, most common is short game practice guideline that 70% of shots occur within 100 metres of green, so you should spend 70% of practice time on short game and 30% on long game, or 70% of improvement comes from short game. Another 70/30 rule in golf is for putting, where 70% of putts are about speed and 30% about line, so focus more on speed control. In golf fitness, 70/30 rule means 70% of power comes from lower body and core, 30% from arms. In golf business, 70/30 rule for pro shop says 70% of revenue from 30% of customers. For junior development, 70/30 rule means 70% of time should be playing on course and 30% practicing on range to keep fun. There is also 70/30 rule for golf club membership, where 70% of members use course 30% of time. Most common coaching 70/30 rule is for practice allocation, spend 70% of practice on short game including putting, chipping, pitching and bunker, and 30% on driving and long irons, because statistics show 70% of strokes are inside 100 yards, and improving short game lowers handicap fastest. So 70/30 is guideline to allocate practice time to short game, not official rule of golf by R&A, but widely taught by PGA coaches.