The range of profits of industry during periods of falling prices will depend upon the nature of the causes which produce the decline. If it is simply the result of an increase in industrial efficiency, or progress in the industrial arts, profits will continue to be satisfactory and may even be on the increase. If, on the other hand, the price decline results from the occurrence of those short periods of forced liquidation known as crises, and is accompanied by that state of recuperative and cautious business activity known as depression, profits in most industries are apt to be quite low. Such was the 1893-96 period in the United States. During the period of forced liquidation and immediately thereafter, the number of bankruptcies is likely to be high.[51] No general statement is possible concerning the duration of such a period of depression and low profits; all accompanying circumstances play a complicating part in retarding or hastening business recovery.--The present depression of 1920-21 is almost of unprecedented duration, for example. Nor should it be supposed that the state of depression must be identical with the period of price decline.[52] Given favorable circumstances, the price decline soon leads to a search for new methods of economy in production. Raw materials are likely to fall in price. Supplementary costs are rapidly reduced. The price of labor tends to fall. Even though prices continue to fall slowly, profits may rise to a level encouraging to business activity. This may also be true of a period of liquidation not preceded by crisis. In conclusion, it can only be repeated, however, that confident generalization as to the direct effects of falling prices is impossible. Each business cycle has its own peculiar characteristics--it is unique as Mitchell says.[53]