Please answer the given financial question based on the context.
Context: ||Gross Carrying Amount|Accumulated Amortization|Net|
|||(in millions)||
|June 30, 2019||||
|Finite-Lived Intangible Assets||||
|Customer relationships|$1,597.6|$(498.7)|$1,098.9|
|Underlying rights and other|3.4|(1.5)|1.9|
|Total|1,601.0|(500.2)|1,100.8|
|Indefinite-Lived Intangible Assets||||
|Certifications|3.5|—|3.5|
|Underlying rights and other|14.5|—|14.5|
|Total|1,619.0|(500.2)|1,118.8|
|June 30, 2018||||
|Finite-Lived Intangible Assets||||
|Customer relationships|$1,597.0|$(405.6)|$1,191.4|
|Underlying rights and other|2.7|(0.6)|2.1|
|Total|1,599.7|(406.2)|1,193.5|
|Indefinite-Lived Intangible Assets||||
|Certifications|3.5|—|3.5|
|Underlying rights and other|15.1|—|15.1|
|Total|$1,618.3|$(406.2)|$1,212.1|
(6) INTANGIBLE ASSETS
Identifiable intangible assets as of June 30, 2019 and 2018 were as follows:
The weighted average remaining amortization period for the Company’s customer relationships asset is 14.3 years. The Company has determined that certain underlying rights (including easements) and the certifications have indefinite lives. The amortization period for underlying rights (including easements) is 13.0 years. The amortization of intangible assets for the years ended June 30, 2019, 2018 and 2017 was $95.1 million, $97.2 million, and $80.0 million, respectively.
Question: How long is the amortization period for underlying rights (including easements)?
Answer:
The amortization period for underlying rights (including easements) is 13.0 years.