By the law of averages, Black Caps are the

New Zealand’s run gorge against England at Bay Oval makes it official: no current test top-seven boasts more batsmen averaging 40-plus.

As the Black Caps transfer to Hamilton to try to close out a fourth successive series win at home, they will do it with six batsmen above the unofficial cutoff for the ‘world class’ tag.

Captain Kane Williamson (52.21), Ross Taylor (46.37), Henry Nicholls (44.16), Tom Latham (43.57), BJ Watling (40.51) and Colin de Grandhomme (40.33) all sit above the line after the Black Caps’ mammoth 615-9 declared in their innings and 65-run victory.

Only opener Jeet Raval, with a still-respectable 34.15, sits outside the 40-plus club.

It’s a safe bet New Zealand have never had such a prolific top-seven. On the all-time list of highest averages (20 innings minimum), Williamson is on top ahead of Taylor, with Nicholls eighth, Latham ninth, Watling 11th and de Grandhomme 12th.

Of the other leading test sides, India and Australia both have five batsmen averaging 40-plus from their lineups for justcompleted wins over Bangladesh and Pakistan respectively.

England and South Africa have just one apiece: their respective skippers Joe Root (47.35) and Faf du Plessis (41.66).

Black Caps coach Gary Stead saw the stats as a badge of honour for his side, with one qualifier.

‘‘I didn’t know those stats but when you’ve got six of the topseven in that area and the other in the mid-30s as well, that augurs well for you scoring enough runs in tests,’’ he said.

‘‘We’ve done that really well in home conditions and our challenge has always been to keep doing it away from home. After this next test it’s about doing it in Australia and other places like we did in Abu Dhabi or Sri Lanka, and the next one will be Bangladesh.’’

Watling’s career figure charged into the 40-plus zone after his 105 not out against Sri Lanka in Colombo then 205 off 473 balls against England, in which he batted a combined 16 hours