Entity information:
INCOME TAXES

The details of income tax expense are as follows: 
 
 
Years Ended September 30
 
 
2017
 
2016
 
2015
 
Current income taxes:
 
 
 
 
 
 
Federal
$
72,368

 
$
(1,216,745
)
 
$
379,180

 
State
407,643

 
415,975

 
374,541

 
Total current income taxes
480,011

 
(800,770
)
 
753,721

 
Deferred income taxes:
 
 
 
 
 
 
Federal
3,129,925

 
4,302,906

 
2,289,729

 
State
195,454

 
164,048

 
127,112

 
Total deferred income taxes
3,325,379

 
4,466,954

 
2,416,841

 
Total income tax expense
$
3,805,390

 
$
3,666,184

 
$
3,170,562


Income tax expense for the years ended September 30, 2017, 2016 and 2015 differed from amounts computed by applying the U.S. Federal income tax rate of 34% to earnings before income taxes due to the following:
 
 
 
Years Ended September 30
 
 
2017
 
2016
 
2015
 
Income before income taxes
$
10,038,255

 
$
9,473,050

 
$
8,264,977

 
Income tax expense computed at the federal statutory rate
$
3,413,007

 
$
3,220,837

 
$
2,810,092

 
State income taxes, net of federal income tax benefit
398,044

 
382,815

 
331,091

 
Other, net
(5,661
)
 
62,532

 
29,379

 
Total income tax expense
$
3,805,390

 
$
3,666,184

 
$
3,170,562


The tax effects of temporary differences that give rise to the deferred tax assets and deferred tax liabilities are as follows:
 
 
September 30
 
 
2017
 
2016
 
Deferred tax assets:
 
 
 
 
Allowance for uncollectibles
$
37,752

 
$
29,203

 
Accrued pension and postretirement medical benefits
1,747,429

 
2,532,672

 
Accrued vacation
239,414

 
262,273

 
Over-recovery of gas costs
545,894

 
345,318

 
Costs of gas held in storage
1,009,206

 
1,077,849

 
Deferred compensation
824,281

 
770,868

 
Other
348,833

 
340,121

 
Total gross deferred tax assets
4,752,809

 
5,358,304

 
Deferred tax liabilities:
 
 
 
 
Utility plant
27,630,486

 
24,264,165

 
MVP investment
154,817

 
40,776

 
Other
44,354

 
11,217

 
Total gross deferred tax liabilities
27,829,657

 
24,316,158

 
Net deferred tax liability
$
23,076,848

 
$
18,957,854

The current federal tax expense for fiscal 2016 reflected the effect of 50% bonus depreciation for the entire fiscal year 2016 as well as for nine months of fiscal 2015. The Protecting Americans from Tax Hikes (PATH Act), which extended 50% bonus depreciation for calendar 2015, was signed into law on December 18, 2015, subsequent to the issuance of the Company's September 30, 2015 annual report. As a result, $1,283,925 of deferred taxes that related to fiscal 2015 bonus depreciation were reflected in the fiscal 2016 tax provision, thereby reducing the current tax expense and increasing deferred tax expense by the same amount. The same situation occurred in fiscal 2014 when the extension of 50% bonus depreciation was not signed into law until December 19, 2014, following the issuance of the Company's financial statements for the year ended September 30, 2014. Correspondingly, fiscal 2015 income tax expense included the tax effect of the 50% bonus depreciation for fixed asset additions during the last nine months of fiscal 2014, which resulted in $1,442,211 in deferred tax expense related to fiscal 2014 being included in fiscal 2015. The recording of the effect of the adjustments for bonus depreciation had no effect on total income tax expense, net income or earnings per share. Only the current and deferred components of income tax expense and their corresponding assets and liabilities were affected.
Under the PATH Act, 50% bonus depreciation extends through December 31, 2017, 40% for calendar 2018 and 30% for calendar 2019 with no provision for bonus depreciation after 2019. Virginia tax law does not recognize bonus depreciation; therefore, state income taxes were not impacted by the delayed bonus depreciation extensions.
FASB ASC No. 740 - Income Taxes provides for the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recognized in the financial statements. The Company has evaluated its tax positions and accordingly has not identified any significant uncertain tax positions. The Company’s policy is to classify interest associated with uncertain tax positions as interest expense in the financial statements. Penalties are classified under other expense.
The Company files a consolidated federal income tax return and state income tax returns in Virginia and West Virginia. The federal returns and the state returns for both Virginia and West Virginia for the tax years ended prior to September 30, 2014 are no longer subject to examination.