a   b   i  x          y          ab   oa ob
pan pan 1  0.34679014 0.72680286 2002 1  1
eks pan 2  0.75867996 0.52215111 2002 1  1
wye wye 3  0.20460331 0.33831853 2002 1  1
eks wye 4  0.38139939 0.13418874 2002 1  1
wye pan 5  0.57328892 0.86362447 2002 1  1
zee pan 6  0.52712616 0.49322129 2003 1  1
eks zee 7  0.61178406 0.18788492 2003 1  1
zee wye 8  0.59855401 0.97618139 2003 1  1
hat wye 9  0.03144188 0.74955076 2003 1  1
pan wye 10 0.50262601 0.95261836 2003 1  1
