Space motion sickness: incidence, etiology, and countermeasures (Martina Heer, William Paloski. Autonomic Neuroscience Vol.129, no.1-2, 2006. Pp. 77-79):
Space motion sickness is experienced by 60% to 80% of space travelers during their first 2 to 3 days in microgravity and by a similar proportion during their first few days after return to Earth.
Since $60\% > 50\%$ :), the answer to your question is an unequivocal YES.
Space motion sickness symptoms are similar to those in other forms of motion sickness; they include: pallor, increased body warmth, cold sweating, malaise, loss of appetite, nausea, fatigue, vomiting, and anorexia.
Facts to remember:
NASA's STS program: up to 80% of the U.S. astronauts.
A study on 15 Russian cosmonauts: 13 out of 15.
50% of 72 U.S. astronauts reported various space motion sickness symptoms.
It doesn't matter whether you have flown before.
Space sickness hits both males and females.