Denmark has as much labor mobility as the United States

According to Daniel Schwammenthal (WSJ, April), about 30 percent of the Danish work force changes jobs each year.  There are few guarantees of job security, and the Danish government spends a great deal of worker retraining.   These training recipients face strong moral and financial pressure to take jobs which are offered to them.  There is also a new NBER paper on the miracle of the Danish labor force.

…we briefly describe some key features of the labor market in Denmark, some of which contribute to the Danish labor markets behaving quite differently from those in many other European countries…We show that mobility is about as high, or even higher, as in the highly fluid U.S. labor market. Finally, we describe and examine the wage structure between and within firms and changes therein since 1980, especially with an eye on possible impacts of the trend towards a more decentralized wage determination. The shift towards decentralized wage bargaining has coincided with deregulation and increased product market competition. The evidence is, however, not consistent with stronger competition in product markets eroding firm-specific rents. Hence, the prime suspect is the change in wage setting institutions.

Starting in the late 1980s, wage bargaining in Denmark became increasingly decentralized, and that is considered to be a major reason for Danish labor market successes.