fev1 is forced expiratory volume or the amount of air you can forcibly exhale in one second. yours has been dropping over the last 4 years at a greater rate than would be expected due to age. fev1 numbers do go down normally as you get older but yours are above that. at 59% of expected fev1 you are now in the moderately obstructed category. Your 2011 numbers showed you to be mildly obstructed.Expected results are based on age, weight, height and believe or not ethnicity and yours are 59% of what would be expected for your age, weight, height and ethnicity in a normal person.
do you have your FVC numbers and fev1/fvc ratio?

my fev1 has gone down from 115% of expected in 2001( i was a runner) to 48% now just to give you one example of progression.