Is the sharemarket a zero sum game or loss making game?

e.g if u lose 10%in value i.e 100 became 90, u need to earn back 10, ie 11% to gain back to 100. conversely, if u earn 10%, ie 100 to 110, and u lose back 10% of 110) , u are back to 99 and not 100. Does that mean we are more likely to lose than win?