WILLBROS GROUP INC DEL

CUSIP: 969203108 Class: COMMON STOCK

CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM's Holding History (CIK: 0001081019)

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

Q4 2017
Shares 69,587 Value ($000) $99 Avg Close — Range —
Q3 2017
Shares 72,087 Value ($000) $232 Avg Close — Range —
Q2 2017
Shares 77,687 Value ($000) $192 Avg Close — Range —
Q1 2017
Shares 86,987 Value ($000) $238 Avg Close — Range —
Q4 2016
Shares 88,987 Value ($000) $288 Avg Close — Range —
Q3 2016
Shares 90,187 Value ($000) $170 Avg Close — Range —
Q2 2016
Shares 90,687 Value ($000) $229 Avg Close — Range —
Q1 2015
Shares 72,786 Value ($000) $241 Avg Close — Range —
Q4 2014
Shares 74,186 Value ($000) $465 Avg Close — Range —
Q3 2014
Shares 73,870 Value ($000) $615 Avg Close — Range —
Q2 2014
Shares 73,151 Value ($000) $903 Avg Close — Range —
Q1 2014
Shares 72,651 Value ($000) $917 Avg Close — Range —
Q4 2013
Shares 72,151 Value ($000) $680 Avg Close — Range —
Q3 2013
Shares 71,851 Value ($000) $660 Avg Close — Range —
Q2 2013
Shares 69,668 Value ($000) $428 Avg Close — Range —
Q1 2013
Shares 67,563 Value ($000) $663 Avg Close — Range —