I would hazard a guess you could make 99.5% of transactions with EFTPOS in NZ - the exceptions might be a few vendors at farmers markets (most take EFTPOS), sausage sizzles/ad-hoc fundraisers, fruit honesty boxes on the side of the road, etc. Maybe only 85% would take credit/debit, though.
From my experience in sydney/melbourne more places take credit/debit than NZ but also more places are cash only. Not as much penetration for EFTPOS.
Works for taxis too. An acquaintance of mine has regularly (once or twice a week) had to travel from his home to the airport, about a $100 fare each way. He's used the same taxi driver for about 10 years - knowing that either this driver (or someone the driver vouches for) will be on time every time.
(taxi expenses are covered by his work but personal car travel is not, so he doesn't drive, go figure)
From my experience in sydney/melbourne more places take credit/debit than NZ but also more places are cash only. Not as much penetration for EFTPOS.