"We average 15 passes a week and the pass rate for the service as a whole is 99 per cent."
As demand for the iHow services increases, it is now offered in Levin, Foxton, Shannon and Sanson, with a trickle of people coming from Dannevirke and Woodville.
The co-ordinator of iHow, Suzanne Carpenter, said when the service first started the target was 100 licensed drivers a year.
"We're now well above that with 638 drivers passing their learner licences with the help of iHow in 2011. Considering that we have now passed the 300 mark and we aren't even halfway through the 2012/2013 year yet, it's reasonable to assume we will top this again.
"Each year, our numbers climb higher and higher."
Ms Carpenter says the secret to iHow's success is in the hands-on teaching method.
"Because the tutors use kinaesthetic, interactive methods, they are more effective for those who struggle with the written word.
"The process consists of two to three hours of teaching in the caravan, on-road revision during the drive to a testing facility and the support of an iHow volunteer who sits with a person while they complete their test.
"It's the only place you can come to and do it all in one day and we are so confident of our teaching methods that we will pay the re-sit fee if they fail."
As well as learner licensing, iHow offers restricted and full licence advice, fines advice, assistance with truck licences and motorcycle licences, and can arrange the ordering of birth certificates.