Data on tenured and untenured college instructors are overviewed by a bit in the Chronicle of Higher Education. They included this old chart and indicated that the numbers for 2009 are expected to worsen.
Innocuously titled "Employees in Postsecondary Institutions, Fall 2009," the report won't say it's about the demise of tenure. But that's what it will show.
Over just three decades, the proportion of college instructors who are tenured or on the tenure track plummeted: from 57 percent in 1975 to 31 percent in 2007. The new report is expected to show that that proportion fell even further in 2009, dropping below one-third. If you add graduate teaching assistants to the mix, those with some kind of tenure status represent a mere quarter of all instructors.
This lack of institutional commitment affects the side of academic employment that focuses on primary research too. In our case it is the expansion of so-called soft-money jobs. These are those in which one's professorial appointment (tenure or not) depends on the ability to hold major research grant funding. From sources outside of the local University, of course.
You can blather on all you like about academic freedom and whinge about the good old days. Spout about quality of education and instruction.
But this is about management-labor economics, pure and simple.
The situation will not improve until the Professoriat understands that they are nothing more or less than labor and responds accordingly. With unified action.