"There are a lot more people coming in and asking about things in the book," said Mrs McCoy, whose family has run adult stores under the Aristocrat name in Tauranga for 20 years. "The age range varies hugely but some of those have been older people."
Fifty Shades of Grey is a 2011 erotic novel by British author E L James which traces the relationship between college graduate Anastasia Steele and young entrepreneur Christian Grey. It features erotic scenes, including sexual practices such as bondage/discipline, dominance/submission and sadism/masochism.
Last month, Whitcoulls ranked it at No5 in its 100 most favoured books list this year, as voted by readers. Part of a trilogy, volumes two and three are titled Fifty Shades Darker and Fifty Shades Freed.
The series has proved hugely popular with women especially, which led to it being dubbed "mummy porn".
"A lot of women seem to be reading it but it's a book that guys should read as well," said Mrs McCoy. "There's enough in there to give the man some inspiration as well, which can only be beneficial. It's about people having fun, at the end of the day."
Mrs McCoy's daughter Caroline, who manages the Aristocrat Adult Boutique, echoed her mother's sentiments.
"It's just normal, everyday people having some fun in life," she said. "I love my job because you know that when people leave here they're going to have a smile on their face, at the end of the day. There are not many jobs you can say that about."
The owner of Adult World, in Cameron Rd, Tauranga, said his sales had increased by a similar amount but it was the level of inquiries that was most surprising.
"It's definitely noticeable and I would say 5 per cent would be about right. But the inquiries have been a lot more than that. We get a lot of people phoning and asking if we have particular toys or items that are mentioned in the book," he said.
The owner, who did not want to be named, said whips, light bondage equipment and sex toys formed the basis of those inquiries.
"It's definitely a positive and people are becoming more accepting of physical pleasures. It doesn't tickle everyone's fancy, of course, but there has certainly been a lot of interest."
The book had opened people's eyes and "people were experimenting more to towards the disciplinary side," he said.
"It has helped people accept that more, that experimenting a little bit can be fun. Anybody out there that has felt nervous in the past can put those feelings aside and hopefully they will be pleasantly surprised."
He added that Fifty Shades of Grey had helped break down barriers and had got people talking about their sex lives. He said sex was a normal part of life whatever your age.
"I have customers ranging in age from 18 to 92. I have a 92-year-old woman who comes in here about every six months. There are no barriers, not on age, gender, race or sexual orientation. There's a whole range of people coming in.
"People have a preconceived idea of what they might have heard in the past about adult shops but it has changed. I've been in the industry for 28 years and I would say up to 18 years ago people might have been looking over their shoulder coming into a store like this but not any more. That has long gone. We have a lot of people coming in for hen parties, 21st birthdays, lingerie and novelty items. We get a lot of women coming in now."
