import re
String1 = " I have total exp of 10-11 years. This includes 15 years in SAS and 5 years in python. I also have 8 months of exp in R programming."
reg = r'\b\d{1,2}(?:\D+\d{1,2})?\D+(?:year|month)s?\b'
print(re.findall(reg, String1))
aW1wb3J0IHJlClN0cmluZzEgPSAiIEkgaGF2ZSB0b3RhbCBleHAgb2YgMTAtMTEgeWVhcnMuIFRoaXMgaW5jbHVkZXMgMTUgeWVhcnMgaW4gU0FTIGFuZCA1IHllYXJzIGluIHB5dGhvbi4gSSBhbHNvIGhhdmUgOCBtb250aHMgb2YgZXhwIGluIFIgcHJvZ3JhbW1pbmcuIgpyZWcgPSByJ1xiXGR7MSwyfSg/OlxEK1xkezEsMn0pP1xEKyg/OnllYXJ8bW9udGgpcz9cYicKcHJpbnQocmUuZmluZGFsbChyZWcsIFN0cmluZzEpKQo=