http://en.wikipedia.org/wiki/Leap_seconds
"Originally, the second was defined as 1/86400 of a mean solar day (see solar time) as determined by the rotation of the Earth around its axis and around the Sun. By the middle of the 20th century, it was apparent that the rotation of the Earth did not provide a sufficiently uniform time standard and in 1956 the second was redefined in terms of the annual orbital revolution of the Earth around the Sun. In 1967 the second was redefined, once again..."
Leap seconds are proof you cannot quantify the measurement of one year because numbers on paper cannot define reality.
"Originally, the second was defined as 1/86400 of a mean solar day (see solar time) as determined by the rotation of the Earth around its axis and around the Sun. By the middle of the 20th century, it was apparent that the rotation of the Earth did not provide a sufficiently uniform time standard and in 1956 the second was redefined in terms of the annual orbital revolution of the Earth around the Sun. In 1967 the second was redefined, once again..."
Leap seconds are proof you cannot quantify the measurement of one year because numbers on paper cannot define reality.