To discuss percentages, first allow me to focus on a tiny group of male techies in Singapore — the only group i know.
Note: Manager roles can cover team size of 2 to 20.
— top n
40% Job: some job outside IT. These folks get out of IT before 55.
10% Job: company owner, CEO, country manager — #1 guy in an office.
5% Job: manager in “infrastructure support” (defined below ). These roles are similar and sometimes indistinguishable. Large systems need a support “team”.
5% Job: manager in app development AND app support. A standard combination.
2% Job: manager in app development, architect, PrjMgr, but without support responsibility. These roles are often combined. Compared to support jobs, such a dev role is rather tiring at age 55.
2% Job: pre-sales + professional service + trainer. Manager or foot soldier. These roles are often combined.
Job: sales, marketing (manager) in a tech firm
Job: government officer, excluding infrastructure support
Job: full time teaching (IT) in private/public instutitions + some R&D.
Job: Business Analyst
Job: senior DBA, system admin or network admin, but not a manager. at age 55?.
Job: manager in product support. Only large product vendors need a support organization.
Job: full time R&D in public/private (large) labs + some teaching. R&D is always an “elite” activity.
Job: full time trainer
Job: writer + trainer
Job: recruiter. Some IT professionals are suitable for this role.
— Job descriptions above usually combine these job functions below, most of them project functions. Multiple project functions are frequently carried out by the same individual, since someone strong in one function can take up another function.
* function: pre-sales consulting
* function: business anlysis
* function: development + design + architect
* function: project management, implemetation rollout management
* function: professional service consulting
* function: engagement manager, account manager, onsite or offsite
* functino: testing
Functions below are not project roles, though the individuals in these functions also take part in projects.
*  function: infrastructure support serving internal users rather than external customers
** app support, after application development and rollout
** operations support
** web master,
** windows application support, such as email or Excel support
** network admin
** Unix/Windows system admin,
** email server support — Exchange, Lotus Notes…
** storage support
** ERM system admin
** CRM system admin
** mobile and remote access support — Citrix, Blackberry
** IT security admin
* function: product support serving external customers, often loosely known as tech support
* function: customer service, often loosely known as tech support
* function: sales support (not pre-sales consulting)
* function: marketing support
* function: training
* function: teaching
* function: research
* function: writer, editor, reporter, reviewer
* function: IT auditing
Most of the age 55 jobs are likely to *combine* these job functions.