How many people are still using the 4.0 series of the Netscape
browser? This includes 4.0, 4.5, 4.67 and any others in the 4 version.

According to this site, about 4%. But as they disclaim, different
types of sites do attract different user bases.

http://www.w3schools.com/browsers/browsers_stats.asp

"Only 2% of the browsing population still uses Netscape 4.x, according
to the global stats on thecounter.com."

Gear Factory Network
http://www.gearfactory.net/netscape4x.php

"Looking at my logs, for example, the total number of Netscape users
visiting the site is less than three percent, and Netscape 4.x users
are less than 1.6% of the total."

Google Groups: comp.publish.prepress newsgroup post
http://groups.google.com/groups?selm=uKfj9.206170%24AR1.8647198%40bin2.nnrp.aus1.giganews.com&oe=UTF-8&output=gplain

As you can see - mileage varies, depending on which statistics you
want to look at.

I am a web designer and maintain about 40 sites on the internet. I
keep track of web stats and browser types for them and have found that
their individual sites vary from 5% to 28% using the Netscape 4.x
browser.

I do know that a great many financial institutions have their entire
intranets built on the Netscape 4.7x browser, which is the only
browser in use on about 4.5 million computers right there alone.

It's hard to pinpoint, but they are still in use, and most of the
larger ecommerce sites still design for those users.

Serenata

Unfortunately, a number of corporate and university ICT departements
(including Oxford) have yet to get around to blanket updating of their
systems.  If you are coding for an academic audience, assume the
lowest common denominator.

Although there are no hard numbers from the graph on the following
page:
://www.google.com/press/zeitgeist.html

it looks like the number of people using Netscape 4.x browers to
access google is declining.