The UK Health and Safety Executive (HSE) does collect and publish stats about illness types by (civilian) profession, including stress-related illnesses. Look at http://www.hse.gov.uk/statistics/causdis/stress/ for more info on that. Teaching regularly figures in the top 5, with about 2-3% stress-related illness rates. Military jobs are excluded from HSE stats but iirc also showed high rates last time I looked.
Whether there is a US equivalent repository I don't know.
Here's some more references on the topic of teacher stress and burnout:
Abel, M. H., & Sewell, J. (1999). Stress and burnout in rural and urban secondary school teachers. Journal of Educational Research, 92(5), 287-293.
Aloe, A., Shisler, S., Norris, B. D., Nickerson, A. B., & Rinker, T. (2014). A multivariate meta-analysis of student misbehavior and teacher burnout. Educational Research Review, 12, 30-44.
Chang, M.-L. (2013). Toward a theoretical model to understand teacher emotions and teacher burnout in the context of student misbehavior: Appraisal, regulation and coping. Motivation and Emotion, 1-19. doi: 10.1007/s11031-012-9335-0.
Guglielmi, R. S., & Tatrow, K. (1998). Occupational stress, burnout, and health in teachers: A methodological and theoretical analysis. Review of Educational Research, 68, 61–99.
Kokkinos, C. M. (2007). Job stressors, personality and burnout in primary school teachers. British Journal of Educational Psychology, 77(1), 229-243.
McCormick, J., & Barnett, K. (2011). Teachers' attributions for stress and their relationships with burnout. International Journal of Educational Management, 25(3), 278-293.
Schaufeli, W. B., Leiter, M. P., & Maslach, C. (2009). Burnout: 35 years of research and practice. Career Development International, 14, 204-220.
Skaalvik, E. M., & Skaalvik, S. (2011). Teacher job satisfaction and motivation to leave the teaching profession: Relations with school context, feeling of belonging, and emotional exhaustion. Teaching and Teacher Education: An International Journal of Research and Studies, 27(6), 1029-1038.
Information regarding stress at teachers is in no way conveniently from ,but this can be observed the teachers attitude,performance his basic nature & behavior between the earlier stage & the present stage of stree behavior .
If one has logical thinking & behavior of teacher,he can certainly draw a line of demarcation .A teacher under the stress can be effiectively viewed on the face of the teachers as we all know that the face is a mirror .
Besides such teachers in their performance also can be noticed while they speak & deliver the talk to the students & also in their regular functioning .