The Global Media Intelligence Report, from insights provider eMarketer, put North America's share at 35.5% in 2014, which it expected to remain unchanged out to 2018.
Most of this was attributable to the US (92.9%) and that proportion is only going to get bigger as Canada's share was slated to dip below 7% by 2016 and continue to decline as adspend there grows more slowly than in its larger neighbour.
Further south, Latin America's share of the global total marginally exceeds that of Canada, standing at 7.3% in 2014 and is projected to increase to 8.4% by 2018, making it the biggest regional gainer.
Within that, Brazil will account for more than half of all adspend, its total predicted to grow from $20.43bn in 2014 to $29.50bn in 2018. Mexico ($5.15bn to $6.79bn) and Argentina ($3.78bn to $4.54bn) are a long way behind.
TV is and will remain the most influential ad medium in Latin America with a share of total advertising expenditure above 60%. Internet spending stands at less than 10%, its progress hindered by low levels of broadband penetration.
According to eMarketer estimates, only 11.7% of the population in the region will subscribe to a broadband service in 2014. And less than one third of households have a fixed connection to the internet, compared with over 67% in Western Europe and 74.6% in North America.
Despite North America being so far advanced in terms of digital, eMarketer expected advertising spending on digital platforms there would grow faster than in any other region between 2014 and 2018.
Within the US, more than 30 cents of every ad dollar will be spent on digital media in 2015, while Canada will not reach this particular landmark until 2018. Across the whole region average advertising spend per internet user is currently $194.95 and projected to increase by around 50% to pass $296 by 2018.
Data sourced from eMarketer; additional content by Warc staff