Kit sponsors BSR Housewares became the clubs first shirt English football sponsorship during the 1981-82 season. The clubs shirts have been sponsored for the majority of the time since then, although there was no shirt sponsor at the end of the 1993-94 season, after local solicitors Coucher & Shaw were closed down by the Law Society of England and Wales. Unusually for a Premier League club, Albion were again without a shirt sponsor for the start of the 2008-09 campaign, as negotiations with a new sponsor were still ongoing when the season began. The longest-running shirt sponsorship deal agreed by the club ran for seven seasons between 1997 and 2004 with the West Bromwich Building Society. Today the clubs principal sponsor is Ideal Boilers. Other sponsors have included T-Mobile (2004-08), Homeserve (2010-11), Bodog (2011-12), Zoopla (2012-14), QuickBooks (2014-15), Tlcbet (2015-16), K8 group (2016-2017), and Palm Eco-Town Development (2017-18).
Question: How many years longer did T-Mobile's sponsorship last compared to QuickBooks' sponsorship?
Answer: 3