Almost half of the world's population will have regular Internet access by 2018, according to a new forecast.

Market research company eMarketer predicts that by then, 3.6 billion people will access the Internet at least once a month.

"While highly developed nations are nearly saturated in terms of Internet users, there's significant room for growth in emerging markets," eMarketer Senior Forecasting Analyst Monica Peart said in a statement. "For example, India and Indonesia will each see double-digit growth in each year between now and 2018." 

Below are eMarketer's predicted milestones from now until 2018:

2014: Brazil will supplant Japan as the 4th largest internet user population

2015: Mexico will move into the 8th spot, eclipsing Germany

2016: India will jump the US as the 2nd largest internet user population

2017: Indonesia will reach the top 5, overtaking Japan

2018: China will eclipse three-quarters of a billion users, after showing accelerating growth in each year in our forecast 

In the short-term, the number of Internet users worldwide will increase 6.2 percent, bringing the total number of those online to more than 3 billion, or 42.2 percent of the global population.

Over the past couple years, both Google and Facebook have talked up the opportunity to bring Internet connectivity to areas of the world that don't yet have it.

In June of 2013, Google launched Project Loon, a network of hot air balloons that travel through the stratosphere -- above airplanes and weather -- to deliver Internet access to people in rural and remote areas.

Google recently announced that its balloons now stay afloat for at least 100 days and that the company has the ability to launch 20 balloons each day.

In 2013, Facebook also launched a new initiative called Internet.org, which is a partnership with communication technology companies like Nokia, Qualcomm and Samsung that aims to expand current network technology to unconnected parts of the world.

EMarketer, which gets its data "from a variety of research firms, government agencies, media outlets and company reports," doesn't delineate the role that these individual efforts have played in expanding Internet access over the past year.

Peart says inexpensive mobile phones and mobile broadband connections are key drivers of Internet access expansion.

Below are the top 25 companies in terms of Internet users in 2014.