The cell phone market has grown significantly since 1990 due to investments in infrastructure that reached 98% completion in the US by 2001, allowing providers to focus on more efficient network equipment and sign on more customers per dollar. As providers became profitable covering 85% of infrastructure costs by 2002, they expanded globally by developing new markets in other countries directly or through joint ventures, tapping into cheaper capital and growing the worldwide user base to over 1 billion subscribers by 2005.