A 1995 survey of 365 IT managers found that only 16% of IT projects were successful (on time and on budget). Some 31% were impaired or canceled –– total failures. Another 53% were project-challenged, a diplomatic way of saying that they were over budget, late, and/or failed to deliver all that was promised.
Ten years later, the percentage for success has reportedly climbed to 29% from 16%. Failures have decreased to 18% from 31%. But "challenged" is holding steady at 53%.
That's not great, but maybe it's not so bad for an industry in which products are never finished or perfect, just less broken.