Thanks for an interesting question.
I checked several sites that regularly collect and summarize
demographic information on internet use around the world. As I
mentioned earlier, there does not appear to be a single, global
breakdown of internet use by different age groups.
However, with a bit of estimation, we can arrive at a reasonable number.
The statistics on worlwide internet use are summarized here:
Worldwide Internet Population 2004: 934 million
Projection for 2005: 1.07 billion
The table also includes the number of internet users in each country,
which may be of itnerest to you.
Age distribution information is available for a few individual
countries, as I've summarized below:
Most Chinese Internet users belonged to the 18 to 24 age group:
Under 18: 17.1%
Above 60: 0.8%
You can see from the above numbers that the under 18-35 year olds
account for 17.1 + 39.1 +17.2 = 73.4% of total users, although this
includes a chunk of under-15 year olds.
Age: the majority (30%) belonged to the 35-49 age group (24% to the
15-24 age group; 27% to the 25-34 age group and 19% to the over 50 age
So for France, the 15-34 year old group that you asked about accounts
for 24 + 27 = 51% of total users.
MORI revealed that during this period, the majority of Internet users
in the country were aged between 16 and 24. Complete details on
statistics on age distribution of Internet users in the Republic of
Ireland between July and September 2004 are available below:
Aged 16-24: 35% of users
Aged 25-34: 29% of users
Aged 35-44: 17% of users
Aged 45-54: 14% of users
Aged 55-64: 7% of users
Aged 65 or above: 2% of users
In Ireland, the figure is 35 + 29 = 64%
MORI revealed that during this month, the majority of Internet users
in the country were those aged between 35 and 44, although there was
an increase in the percentages in the older age groups. Complete
details on statistics on age distribution of Internet users in Great
Britain in February 2005 are available below:
Aged 15-24: 19% of users
Aged 25-34: 19% of users
Aged 35-44: 24% of users
Aged 45-54: 19% of users
Aged 55-64: 13% of users
Aged 65 or over: 6% of users
The UK internet users appear to be a bit older, with the 15-34 year
olds accounting for 19 + 19 = 38%
The Online Publishers Association (OPA) has released the first in a
series of research reports designed to provide a detailed view of the
18 to 34 year-old consumer. The research, conducted in partnership
with comScore Networks, found that 72% of all 18 to 34 year-olds are
online - the highest percentage of any age group.
Notably, 18 to 34 year-olds account for a significantly larger share
of Internet usage relative to their proportion in the total US
population. While 18 to 34 year-olds comprise only 24% of the total US
population, they account for 38% of the total time spent online and
40% of the total pages viewed. This is even more pronounced among men
in this age group.
Internet users by age group (with in bracket the equivalent as a % of
the total adult online population) are as follows:
Age 18+: 79.08 million
Men aged 18+: 39.84 million (50.4%)
Women aged 18+: 39.24 million (49.6%)
Aged 18-20: 4.98 million (6.3%)
Aged 21-24: 6.33 million (8.0%)
Aged 25-34: 17.91 million (22.6%)
Aged 45-49: 19.93 million (23.9%)
Aged 45-49: 8.87 million (11.2%)
Aged 50-54: 7.60 million (9.6%)
Aged 55-64: 8.95 million (11.3%)
Aged 65-74: 4.27 million (5.4%)
Aged 75+: 1.25 million (1.6%)
So the figure for the US is 38% for the 18-34 year olds, although this
misses out on the very active 15-17 year old segment.
[This information about Sweden only shows the percent of age groups
who use the internet, so it can't really be compared to the above
numbers. I've included the link just for the sake of completeness]
"Facts About the Information and Communications Technology in Sweden 2004"
Home Internet usage by age group: (as % of age group)
16-24 years old: 97%
25-34 years old: 91%
35-44 years old: 87%
45-54 years old: 74%
55-64 years old: 69%
65-74 years old: 25%
So, the percents do range a bit, but overall I think that 55% is a
typical percentage for the 15-34 year olds that you asked about. With
about 1 billion people online in 2005 (up from 934 million in 2004),
then about 550 million of them would be in the 15-34 year old age
I have not seen country break-outs for age groups other than the ones
above, so I'm not sure you would get a lot of additional information
with a follow-up question. However, there's always a chance that
another researcher could come up with something that I didn't spot
this first time around.
I trust this is the information you needed. But before rating this
answer, please let me know if there's anything else I can do for you.
Just post a Request for Clarification, and I'm at your service.
All the best,
search strategy -- Used bookmarked sites for internet demographics.