Here's an interesting article about this industry.
http://nashville.bizjournals.com/nashville/stories/1998/03/09/focus1.html

"The Tennessee Department of Employment Security reports the janitorial and cleaning industries will continue to be one of the fastest-growing segments of the economy for the next decade. Not only is demand increasing because of new buildings, but also because the janitorial industry is not keeping pace with current demand by adding new workers for every worker it loses. The DES reports an estimated 41,650 people were employed in the industry in 1994. By the year 2005, the report says the industry will grow an estimated 26.8 percent and will need 52,820 workers to keep pace with that growth. Service Magazine, a publication of Building Service Contractors Association International, a Fairfax, Va.-based trade organization, reports nationwide employment of janitors and maids will rise 559,000, or 18 percent, between 1994 and 2005"

Also recently I went to a medical office to discuss their maintenance program. The workers were using Pine cleaner on waxed floors. Fortunely the floors were newly waxed & they may have used it only 2 to 3 times. Enough to do real damage but they dodged the bullet. Medical maintenance can be tricky. You really shouldn't use acidic cleaners on sealed floors but bacteria & other biological concerns exist. It really important to choose the right chemicals.