NATURAL GAS SERVICES GROUP

Ticker: NGS CUSIP: 63886Q109 Class: Common Stock

NEW YORK STATE TEACHERS RETIREMENT SYSTEM's Holding History (CIK: 0000314969)

Note: Option positions (PUT/CALL) are excluded.

Q3 2017

Shares 1,100 Value ($000) $31 Avg Close $24.49 Range $22.26 - $29.24

Q2 2017

Shares 1,100 Value ($000) $27 Avg Close $26.24 Range $22.26 - $28.69

Q1 2017

Shares 1,100 Value ($000) $29 Avg Close $27.74 Range $23.30 - $33.05

Q4 2016

Shares 1,100 Value ($000) $35 Avg Close $27.19 Range $20.43 - $34.13

Q3 2016

Shares 1,100 Value ($000) $27 Avg Close $24.06 Range $21.50 - $26.46

Period	Shares	Value ($000)	Average Close	Price Range
Q3 2017	1,100	$31	$24.49	$22.26 - $29.24
Q2 2017	1,100	$27	$26.24	$22.26 - $28.69
Q1 2017	1,100	$29	$27.74	$23.30 - $33.05
Q4 2016	1,100	$35	$27.19	$20.43 - $34.13
Q3 2016	1,100	$27	$24.06	$21.50 - $26.46